feat: give each set its requirement and one pick

Three changes to the search-list model, one commit because the readers and the profiles must move together for the schema to hold. Set requirement in a groups map. pom2 falls back on apple2.rom for the ][ and the ][+, and on apple2e.rom for the //e it boots and for the unenhanced //e: one required on the file could not say both. A profile now declares groups: {name: {required}}, a member writes no required of its own (schema and validate_schemas refuse one) and load_emulator_ profiles derives it, true when one of its sets is. group takes a name, a list, or a map from set to rank where the rank differs per set. pom2 is grouped from SystemProfile.cpp and MainWindow.cpp:246-296 at its pin. One member per required set under --required-only. The pick is the first the code reads among the held members the region filter leaves, by rank then declaration order; a set the platform declares a member of is carried by that declaration. The emulator pack, verify --emulator, the platform pack, its manifest and verify --platform read alternatives.required_only_spares or core_file_spares. variant_group is now selection_slot: files a core chooses between by a rule other than first found (disc territory for PicoDrive and Pizza Boy SC, the o2em_bios option, a WebAssembly probe in SWF Player). Where the code takes any one, the field became a group: ARMSX1 (ArmSxBackend.java:149-157, name order), ePSXe (load_bios 0x433540-0x433621 of the 2.0.5 Linux x64 binary, one configured path, HLE when BiosHLE is set), FPse and FPse-NG, DXX-Rebirth's HOGs (inferno.cpp:472-512). odin and zesarux carried it with no effect. slot.py compares ranks only between candidates that share a set.
2026-11-11 12:33:53 -06:00 · 2026-11-09 18:19:32 +01:00
1 parent 1e12d9fe38
commit 315dab82b7
@@ -71,22 +71,26 @@ notes: |
       frontend/config.c:1384-1405, frontend/config.c:1541-1560,
       frontend/main.cpp:2555-2561, psx/dev/bios.c:22-75

+groups:
+  ps-bios:
+    required: true
+
 files:
  - name: "scph1000.bin"
+    group: ps-bios
+    priority: 4
    description: "SCPH-1000, DTL-H1000 (v1.0)"
    region: [japan]
-    required: false
-    variant_group: "psx-bios"
    size: 524288
    md5: "239665b1a3dade1b5a52c06338011044"
    validation: [size, md5]
    source_ref: "android/app/src/main/java/com/armsx2/core/Ps1BiosProbe.java:30"

  - name: "scph1001.bin"
+    group: ps-bios
+    priority: 6
    description: "SCPH-1001, 5003, DTL-H1201, H3001 (v2.2 12-04-95 A)"
    region: [north-america, latin-america]
-    required: false
-    variant_group: "psx-bios"
    size: 524288
    md5: "924e392ed05558ffdb115408c263dccf"
    validation: [size, md5]
@@ -96,230 +100,230 @@ files:
    source_ref: "android/app/src/main/java/com/armsx2/core/Ps1BiosProbe.java:31"

  - name: "scph1002a.bin"
+    group: ps-bios
+    priority: 9
    description: "SCPH-1002, DTL-H1002 (v2.0 05-10-95 E)"
    region: [europe, oceania]
-    required: false
-    variant_group: "psx-bios"
    size: 524288
    md5: "54847e693405ffeb0359c6287434cbef"
    validation: [size, md5]
    source_ref: "android/app/src/main/java/com/armsx2/core/Ps1BiosProbe.java:32"

  - name: "scph1002b.bin"
+    group: ps-bios
+    priority: 10
    description: "SCPH-1002, DTL-H1102 (v2.1 07-17-95 E)"
    region: [europe, oceania]
-    required: false
-    variant_group: "psx-bios"
    size: 524288
    md5: "417b34706319da7cf001e76e40136c23"
    validation: [size, md5]
    source_ref: "android/app/src/main/java/com/armsx2/core/Ps1BiosProbe.java:33"

  - name: "scph1002c.bin"
+    group: ps-bios
+    priority: 11
    description: "SCPH-1002, DTL-H1202, H3002 (v2.2 12-04-95 E)"
    region: [europe, oceania]
-    required: false
-    variant_group: "psx-bios"
    size: 524288
    md5: "e2110b8a2b97a8e0b857a45d32f7e187"
    validation: [size, md5]
    source_ref: "android/app/src/main/java/com/armsx2/core/Ps1BiosProbe.java:34"

  - name: "dtlh1100.bin"
+    group: ps-bios
+    priority: 1
    description: "DTL-H1100 (v2.2 03-06-96 D)"
    region: [japan]
-    required: false
-    variant_group: "psx-bios"
    size: 524288
    md5: "ca5cfc321f916756e3f0effbfaeba13b"
    validation: [size, md5]
    source_ref: "android/app/src/main/java/com/armsx2/core/Ps1BiosProbe.java:35"

  - name: "scph3000.bin"
+    group: ps-bios
+    priority: 16
    description: "SCPH-3000, DTL-H1000H (v1.1 01-22-95)"
    region: [japan]
-    required: false
-    variant_group: "psx-bios"
    size: 524288
    md5: "849515939161e62f6b866f6853006780"
    validation: [size, md5]
    source_ref: "android/app/src/main/java/com/armsx2/core/Ps1BiosProbe.java:36"

  - name: "scph1001_v20.bin"
+    group: ps-bios
+    priority: 7
    description: "SCPH-1001, DTL-H1001 (v2.0 05-07-95 A)"
    region: [north-america, latin-america]
-    required: false
-    variant_group: "psx-bios"
    size: 524288
    md5: "dc2b9bf8da62ec93e868cfd29f0d067d"
    validation: [size, md5]
    source_ref: "android/app/src/main/java/com/armsx2/core/Ps1BiosProbe.java:37"

  - name: "scph3500.bin"
+    group: ps-bios
+    priority: 17
    description: "SCPH-3500 (v2.1 07-17-95 J)"
    region: [japan]
-    required: false
-    variant_group: "psx-bios"
    size: 524288
    md5: "cba733ceeff5aef5c32254f1d617fa62"
    validation: [size, md5]
    source_ref: "android/app/src/main/java/com/armsx2/core/Ps1BiosProbe.java:38"

  - name: "scph1001_v21.bin"
+    group: ps-bios
+    priority: 8
    description: "SCPH-1001, DTL-H1101 (v2.1 07-17-95 A)"
    region: [north-america, latin-america]
-    required: false
-    variant_group: "psx-bios"
    size: 524288
    md5: "da27e8b6dab242d8f91a9b25d80c63b8"
    validation: [size, md5]
    source_ref: "android/app/src/main/java/com/armsx2/core/Ps1BiosProbe.java:39"

  - name: "scph5000.bin"
+    group: ps-bios
+    priority: 18
    description: "SCPH-5000, DTL-H1200, H3000 (v2.2 12-04-95 J)"
    region: [japan]
-    required: false
-    variant_group: "psx-bios"
    size: 524288
    md5: "57a06303dfa9cf9351222dfcbb4a29d9"
    validation: [size, md5]
    source_ref: "android/app/src/main/java/com/armsx2/core/Ps1BiosProbe.java:40"

  - name: "scph5500.bin"
+    group: ps-bios
+    priority: 19
    description: "SCPH-5500 (v3.0 09-09-96 J)"
    region: [japan]
-    required: false
-    variant_group: "psx-bios"
    size: 524288
    md5: "8dd7d5296a650fac7319bce665a6a53c"
    validation: [size, md5]
    source_ref: "android/app/src/main/java/com/armsx2/core/Ps1BiosProbe.java:41"

  - name: "scph5501.bin"
+    group: ps-bios
+    priority: 20
    description: "SCPH-5501, 5503, 7003 (v3.0 11-18-96 A)"
    region: [north-america, latin-america]
-    required: false
-    variant_group: "psx-bios"
    size: 524288
    md5: "490f666e1afb15b7362b406ed1cea246"
    validation: [size, md5]
    source_ref: "android/app/src/main/java/com/armsx2/core/Ps1BiosProbe.java:42"

  - name: "scph5502.bin"
+    group: ps-bios
+    priority: 21
    description: "SCPH-5502, 5552 (v3.0 01-06-97 E)"
    region: [europe, oceania]
-    required: false
-    variant_group: "psx-bios"
    size: 524288
    md5: "32736f17079d0b2b7024407c39bd3050"
    validation: [size, md5]
    source_ref: "android/app/src/main/java/com/armsx2/core/Ps1BiosProbe.java:43"

  - name: "scph7000.bin"
+    group: ps-bios
+    priority: 22
    description: "SCPH-7000, 7500, 9000 (v4.0 08-18-97 J)"
    region: [japan]
-    required: false
-    variant_group: "psx-bios"
    size: 524288
    md5: "8e4c14f567745eff2f0408c8129f72a6"
    validation: [size, md5]
    source_ref: "android/app/src/main/java/com/armsx2/core/Ps1BiosProbe.java:44"

  - name: "scph7000w.bin"
+    group: ps-bios
+    priority: 23
    description: "SCPH-7000W (v4.1 11-14-97 A)"
    region: [japan]
-    required: false
-    variant_group: "psx-bios"
    size: 524288
    md5: "b84be139db3ee6cbd075630aa20a6553"
    validation: [size, md5]
    source_ref: "android/app/src/main/java/com/armsx2/core/Ps1BiosProbe.java:45"

  - name: "scph7001.bin"
+    group: ps-bios
+    priority: 24
    description: "SCPH-7001, 7501, 7503, 9001, 9003, 9903 (v4.1 12-16-97 A)"
    region: [north-america, latin-america]
-    required: false
-    variant_group: "psx-bios"
    size: 524288
    md5: "1e68c231d0896b7eadcad1d7d8e76129"
    validation: [size, md5]
    source_ref: "android/app/src/main/java/com/armsx2/core/Ps1BiosProbe.java:46"

  - name: "scph7002.bin"
+    group: ps-bios
+    priority: 25
    description: "SCPH-7002, 7502, 9002 (v4.1 12-16-97 E)"
    region: [europe, oceania]
-    required: false
-    variant_group: "psx-bios"
    size: 524288
    md5: "b9d9a0286c33dc6b7237bb13cd46fdee"
    validation: [size, md5]
    source_ref: "android/app/src/main/java/com/armsx2/core/Ps1BiosProbe.java:47"

  - name: "scph100.bin"
+    group: ps-bios
+    priority: 3
    description: "SCPH-100 (v4.3 03-11-00 J)"
    region: [japan]
-    required: false
-    variant_group: "psx-bios"
    size: 524288
    md5: "8abc1b549a4a80954addc48ef02c4521"
    validation: [size, md5]
    source_ref: "android/app/src/main/java/com/armsx2/core/Ps1BiosProbe.java:48"

  - name: "scph101_v44.bin"
+    group: ps-bios
+    priority: 12
    description: "SCPH-101 (v4.4 03-24-00 A)"
    region: [north-america, latin-america]
-    required: false
-    variant_group: "psx-bios"
    size: 524288
    md5: "9a09ab7e49b422c007e6d54d7c49b965"
    validation: [size, md5]
    source_ref: "android/app/src/main/java/com/armsx2/core/Ps1BiosProbe.java:49"

  - name: "scph101_v45.bin"
+    group: ps-bios
+    priority: 13
    description: "SCPH-101 (v4.5 05-25-00 A)"
    region: [north-america, latin-america]
-    required: false
-    variant_group: "psx-bios"
    size: 524288
    md5: "6e3735ff4c7dc899ee98981385f6f3d0"
    validation: [size, md5]
    source_ref: "android/app/src/main/java/com/armsx2/core/Ps1BiosProbe.java:50"

  - name: "scph102_v44.bin"
+    group: ps-bios
+    priority: 14
    description: "SCPH-102 (v4.4 03-24-00 E)"
    region: [europe, oceania]
-    required: false
-    variant_group: "psx-bios"
    size: 524288
    md5: "b10f5e0e3d9eb60e5159690680b1e774"
    validation: [size, md5]
    source_ref: "android/app/src/main/java/com/armsx2/core/Ps1BiosProbe.java:51"

  - name: "scph102_v45.bin"
+    group: ps-bios
+    priority: 15
    description: "SCPH-102 (v4.5 05-25-00 E)"
    region: [europe, oceania]
-    required: false
-    variant_group: "psx-bios"
    size: 524288
    md5: "de93caec13d1a141a40a79f5c86168d6"
    validation: [size, md5]
    source_ref: "android/app/src/main/java/com/armsx2/core/Ps1BiosProbe.java:52"

  - name: "psxonpsp660.bin"
+    group: ps-bios
+    priority: 2
    description: "PSP, SCPH-1000R (v4.5 05-25-00 J)"
    region: [world]
-    required: false
-    variant_group: "psx-bios"
    size: 524288
    md5: "c53ca5908936d412331790f4426c6c33"
    validation: [size, md5]
    source_ref: "android/app/src/main/java/com/armsx2/core/Ps1BiosProbe.java:53"

  - name: "scph1000r.bin"
+    group: ps-bios
+    priority: 5
    description: "SCPH-1000R (v4.5 05-25-00 J)"
    region: [japan]
-    required: false
-    variant_group: "psx-bios"
    size: 524288
    md5: "476d68a94ccec3b9c8303bbd1daf2810"
    validation: [size, md5]
@@ -74,6 +74,10 @@ notes: |
  The libretro core was removed by the author (license change to non-commercial).
  The .info file and buildbot builds still exist from community forks.

+groups:
+  ps-bios:
+    required: true
+
 files:
  # -- PS1 BIOS images (priority <= 20, preferred) --

@@ -82,7 +86,6 @@ files:
    description: "SCPH-1000, DTL-H1000 (v1.0)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "239665b1a3dade1b5a52c06338011044"
    region_check: true
    fast_boot: Type1
@@ -94,7 +97,6 @@ files:
    description: "SCPH-1001, 5003, DTL-H1201, H3001 (v2.2 12-04-95 A)"
    region: [north-america, latin-america]
    group: ps-bios
-    required: true
    md5: "924e392ed05558ffdb115408c263dccf"
    region_check: false
    fast_boot: Type1
@@ -106,7 +108,6 @@ files:
    description: "SCPH-1002, DTL-H1002 (v2.0 05-10-95 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "54847e693405ffeb0359c6287434cbef"
    region_check: false
    fast_boot: Type1
@@ -118,7 +119,6 @@ files:
    description: "SCPH-1002, DTL-H1102 (v2.1 07-17-95 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "417b34706319da7cf001e76e40136c23"
    region_check: false
    fast_boot: Type1
@@ -130,7 +130,6 @@ files:
    description: "SCPH-1002, DTL-H1202, H3002 (v2.2 12-04-95 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "e2110b8a2b97a8e0b857a45d32f7e187"
    region_check: false
    fast_boot: Type1
@@ -142,7 +141,6 @@ files:
    description: "DTL-H1100 (v2.2 03-06-96 D)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "ca5cfc321f916756e3f0effbfaeba13b"
    region_check: true
    fast_boot: Type1
@@ -154,7 +152,6 @@ files:
    description: "SCPH-3000, DTL-H1000H (v1.1 01-22-95)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "849515939161e62f6b866f6853006780"
    region_check: true
    fast_boot: Type1
@@ -166,7 +163,6 @@ files:
    description: "SCPH-1001, DTL-H1001 (v2.0 05-07-95 A)"
    region: [north-america, latin-america]
    group: ps-bios
-    required: true
    md5: "dc2b9bf8da62ec93e868cfd29f0d067d"
    region_check: false
    fast_boot: Type1
@@ -178,7 +174,6 @@ files:
    description: "SCPH-3500 (v2.1 07-17-95 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "cba733ceeff5aef5c32254f1d617fa62"
    region_check: true
    fast_boot: Type1
@@ -190,7 +185,6 @@ files:
    description: "SCPH-1001, DTL-H1101 (v2.1 07-17-95 A)"
    region: [north-america, latin-america]
    group: ps-bios
-    required: true
    md5: "da27e8b6dab242d8f91a9b25d80c63b8"
    region_check: false
    fast_boot: Type1
@@ -202,7 +196,6 @@ files:
    description: "SCPH-5000, DTL-H1200, H3000 (v2.2 12-04-95 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "57a06303dfa9cf9351222dfcbb4a29d9"
    region_check: true
    fast_boot: Type1
@@ -214,7 +207,6 @@ files:
    description: "SCPH-5500 (v3.0 09-09-96 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "8dd7d5296a650fac7319bce665a6a53c"
    region_check: true
    fast_boot: Type1
@@ -226,7 +218,6 @@ files:
    description: "SCPH-5501, 5503, 7003 (v3.0 11-18-96 A)"
    region: [north-america, latin-america]
    group: ps-bios
-    required: true
    md5: "490f666e1afb15b7362b406ed1cea246"
    region_check: false
    fast_boot: Type1
@@ -238,7 +229,6 @@ files:
    description: "SCPH-5502, 5552 (v3.0 01-06-97 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "32736f17079d0b2b7024407c39bd3050"
    region_check: false
    fast_boot: Type1
@@ -250,7 +240,6 @@ files:
    description: "SCPH-7000, 7500, 9000 (v4.0 08-18-97 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "8e4c14f567745eff2f0408c8129f72a6"
    region_check: true
    fast_boot: Type1
@@ -262,7 +251,6 @@ files:
    description: "SCPH-7000W (v4.1 11-14-97 A)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "b84be139db3ee6cbd075630aa20a6553"
    region_check: false
    fast_boot: Type1
@@ -274,7 +262,6 @@ files:
    description: "SCPH-7001, 7501, 7503, 9001, 9003, 9903 (v4.1 12-16-97 A)"
    region: [north-america, latin-america]
    group: ps-bios
-    required: true
    md5: "1e68c231d0896b7eadcad1d7d8e76129"
    region_check: false
    fast_boot: Type1
@@ -286,7 +273,6 @@ files:
    description: "SCPH-7002, 7502, 9002 (v4.1 12-16-97 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "b9d9a0286c33dc6b7237bb13cd46fdee"
    region_check: false
    fast_boot: Type1
@@ -298,7 +284,6 @@ files:
    description: "SCPH-100 (v4.3 03-11-00 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "8abc1b549a4a80954addc48ef02c4521"
    region_check: true
    fast_boot: Type1
@@ -310,7 +295,6 @@ files:
    description: "SCPH-101 (v4.4 03-24-00 A)"
    region: [north-america, latin-america]
    group: ps-bios
-    required: true
    md5: "9a09ab7e49b422c007e6d54d7c49b965"
    region_check: false
    fast_boot: Type1
@@ -322,7 +306,6 @@ files:
    description: "SCPH-101 (v4.5 05-25-00 A)"
    region: [north-america, latin-america]
    group: ps-bios
-    required: true
    md5: "6e3735ff4c7dc899ee98981385f6f3d0"
    region_check: false
    fast_boot: Type1
@@ -334,7 +317,6 @@ files:
    description: "SCPH-102 (v4.4 03-24-00 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "b10f5e0e3d9eb60e5159690680b1e774"
    region_check: true
    fast_boot: Type1
@@ -346,7 +328,6 @@ files:
    description: "SCPH-102 (v4.5 05-25-00 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "de93caec13d1a141a40a79f5c86168d6"
    region_check: true
    fast_boot: Type1
@@ -358,7 +339,6 @@ files:
    description: "SCPH-1000R (v4.5 05-25-00 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "476d68a94ccec3b9c8303bbd1daf2810"
    region_check: true
    fast_boot: Type1
@@ -374,7 +354,6 @@ files:
    description: "PS2, SCPH-18000 (v5.0 10-27-00 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "d8f485717a5237285e4d7c5f881b7f32"
    region_check: true
    fast_boot: Type2
@@ -386,7 +365,6 @@ files:
    description: "PS2, SCPH-30003 (v5.0 09-02-00 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "71f50ef4f4e17c163c78908e16244f7d"
    region_check: true
    fast_boot: Type2
@@ -398,7 +376,6 @@ files:
    description: "PS2, DTL-H10000 (v5.0 01/17/00 T)"
    region: [world]
    group: ps-bios
-    required: true
    md5: "32f2e4d5ff5ee11072a6bc45530f5765"
    region_check: true
    fast_boot: Type2
@@ -410,7 +387,6 @@ files:
    description: "PS2, SCPH-10000 (v5.0 01/17/00 T)"
    region: [world]
    group: ps-bios
-    required: true
    md5: "acf4730ceb38ac9d8c7d8e21f2614600"
    region_check: true
    fast_boot: Type2
@@ -422,7 +398,6 @@ files:
    description: "PS2, DTL-H10000 (v5.0 02/17/00 T)"
    region: [world]
    group: ps-bios
-    required: true
    md5: "acf9968c8f596d2b15f42272082513d1"
    region_check: true
    fast_boot: Type2
@@ -434,7 +409,6 @@ files:
    description: "PS2, SCPH-10000/SCPH-15000 (v5.0 02/17/00 T)"
    region: [world]
    group: ps-bios
-    required: true
    md5: "b1459d7446c69e3e97e6ace3ae23dd1c"
    region_check: true
    fast_boot: Type2
@@ -446,7 +420,6 @@ files:
    description: "PS2, DTL-H10000 (v5.0 02/24/00 T)"
    region: [world]
    group: ps-bios
-    required: true
    md5: "d3f1853a16c2ec18f3cd1ae655213308"
    region_check: true
    fast_boot: Type2
@@ -458,7 +431,6 @@ files:
    description: "PS2, DTL-H30001 (v5.0 07/27/00 A)"
    region: [north-america, latin-america]
    group: ps-bios
-    required: true
    md5: "63e6fd9b3c72e0d7b920e80cf76645cd"
    region_check: true
    fast_boot: Type2
@@ -470,7 +442,6 @@ files:
    description: "PS2, SCPH-30001 (v5.0 07/27/00 A)"
    region: [north-america, latin-america]
    group: ps-bios
-    required: true
    md5: "a20c97c02210f16678ca3010127caf36"
    region_check: true
    fast_boot: Type2
@@ -482,7 +453,6 @@ files:
    description: "PS2, SCPH-30001 (v5.0 09/02/00 A)"
    region: [north-america, latin-america]
    group: ps-bios
-    required: true
    md5: "8db2fbbac7413bf3e7154c1e0715e565"
    region_check: true
    fast_boot: Type2
@@ -494,7 +464,6 @@ files:
    description: "PS2, DTL-H30002 (v5.0 09/02/00 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "91c87cb2f2eb6ce529a2360f80ce2457"
    region_check: true
    fast_boot: Type2
@@ -506,7 +475,6 @@ files:
    description: "PS2, DTL-H30102 (v5.0 09/02/00 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "3016b3dd42148a67e2c048595ca4d7ce"
    region_check: true
    fast_boot: Type2
@@ -518,7 +486,6 @@ files:
    description: "PS2, SCPH-30002/SCPH-30003/SCPH-30004 (v5.0 09/02/00 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "b7fa11e87d51752a98b38e3e691cbf17"
    region_check: true
    fast_boot: Type2
@@ -530,7 +497,6 @@ files:
    description: "PS2, SCPH-18000 (GH-003) (v5.0 10/27/00 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "f63bc530bd7ad7c026fcd6f7bd0d9525"
    region_check: true
    fast_boot: Type2
@@ -542,7 +508,6 @@ files:
    description: "PS2, SCPH-18000 (GH-008) (v5.0 10/27/00 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "cee06bd68c333fc5768244eae77e4495"
    region_check: true
    fast_boot: Type2
@@ -554,7 +519,6 @@ files:
    description: "PS2, DTL-H30101 (v5.0 12/28/00 A)"
    region: [north-america, latin-america]
    group: ps-bios
-    required: true
    md5: "0bf988e9c7aaa4c051805b0fa6eb3387"
    region_check: true
    fast_boot: Type2
@@ -566,7 +530,6 @@ files:
    description: "PS2, SCPH-30001/SCPH-35001 (v5.0 12/28/00 A)"
    region: [north-america, latin-america]
    group: ps-bios
-    required: true
    md5: "8accc3c49ac45f5ae2c5db0adc854633"
    region_check: true
    fast_boot: Type2
@@ -578,7 +541,6 @@ files:
    description: "PS2, DTL-H30102 (v5.0 12/28/00 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "6f9a6feb749f0533aaae2cc45090b0ed"
    region_check: true
    fast_boot: Type2
@@ -590,7 +552,6 @@ files:
    description: "PS2, SCPH-30002/SCPH-30003/SCPH-30004/SCHP-35002/SCPH-35003/SCPH-35004 (v5.0 12/28/00 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "838544f12de9b0abc90811279ee223c8"
    region_check: true
    fast_boot: Type2
@@ -602,7 +563,6 @@ files:
    description: "PS2, DTL-H30000 (v5.0 01/18/01 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "bb6bbc850458fff08af30e969ffd0175"
    region_check: true
    fast_boot: Type2
@@ -614,7 +574,6 @@ files:
    description: "PS2, SCPH-30000/SCPH-35000 (v5.0 01/18/01 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "815ac991d8bc3b364696bead3457de7d"
    region_check: true
    fast_boot: Type2
@@ -626,7 +585,6 @@ files:
    description: "PS2, SCPH-30001R (v5.0 04/27/01 A)"
    region: [north-america, latin-america]
    group: ps-bios
-    required: true
    md5: "b107b5710042abe887c0f6175f6e94bb"
    region_check: true
    fast_boot: Type2
@@ -638,7 +596,6 @@ files:
    description: "PS2, SCPH-30000 (v5.0 04/27/01 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "ab55cceea548303c22c72570cfd4dd71"
    region_check: true
    fast_boot: Type2
@@ -650,7 +607,6 @@ files:
    description: "PS2, SCPH-30001R (v5.0 07/04/01 A)"
    region: [north-america, latin-america]
    group: ps-bios
-    required: true
    md5: "18bcaadb9ff74ed3add26cdf709fff2e"
    region_check: true
    fast_boot: Type2
@@ -662,7 +618,6 @@ files:
    description: "PS2, SCPH-30002R/SCPH-30003R/SCPH-30004R (v5.0 07/04/01 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "491209dd815ceee9de02dbbc408c06d6"
    region_check: true
    fast_boot: Type2
@@ -674,7 +629,6 @@ files:
    description: "PS2, SCPH-30001R (v5.0 10/04/01 A)"
    region: [north-america, latin-america]
    group: ps-bios
-    required: true
    md5: "7200a03d51cacc4c14fcdfdbc4898431"
    region_check: true
    fast_boot: Type2
@@ -686,7 +640,6 @@ files:
    description: "PS2, SCPH-30002R/SCPH-30003R/SCPH-30004R (v5.0 10/04/01 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "8359638e857c8bc18c3c18ac17d9cc3c"
    region_check: true
    fast_boot: Type2
@@ -698,7 +651,6 @@ files:
    description: "PS2, SCPH-30005R/SCPH-30006R/SCPH-30007R (v5.0 07/30/01 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "352d2ff9b3f68be7e6fa7e6dd8389346"
    region_check: true
    fast_boot: Type2
@@ -710,7 +662,6 @@ files:
    description: "PS2, SCPH-39001 (v5.0 02/07/02 A)"
    region: [north-america, latin-america]
    group: ps-bios
-    required: true
    md5: "d5ce2c7d119f563ce04bc04dbc3a323e"
    region_check: true
    fast_boot: Type2
@@ -722,7 +673,6 @@ files:
    description: "PS2, SCPH-39002/SCPH-39003/SCPH-39004 (v5.0 03/19/02 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "0d2228e6fd4fb639c9c39d077a9ec10c"
    region_check: true
    fast_boot: Type2
@@ -734,7 +684,6 @@ files:
    description: "PS2, SCPH-37000/SCPH-39000 (v5.0 04/26/02 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "72da56fccb8fcd77bba16d1b6f479914"
    region_check: true
    fast_boot: Type2
@@ -746,7 +695,6 @@ files:
    description: "PS2, SCPH-39008 (v5.0 04/26/02 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "5b1f47fbeb277c6be2fccdd6344ff2fd"
    region_check: true
    fast_boot: Type2
@@ -758,7 +706,6 @@ files:
    description: "PS2, SCPH-39005/SCPH-39006/SCPH-39007 (v5.0 04/26/02 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "315a4003535dfda689752cb25f24785c"
    region_check: true
    fast_boot: Type2
@@ -770,7 +717,6 @@ files:
    description: "PS2, DTL-H50000 (v5.0 02/06/03 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "54ecde087258557e2ddb5c3ddb004028"
    region_check: true
    fast_boot: Type2
@@ -782,7 +728,6 @@ files:
    description: "PS2, SCPH-50000/SCPH-55000 (v5.0 02/06/03 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "312ad4816c232a9606e56f946bc0678a"
    region_check: true
    fast_boot: Type2
@@ -794,7 +739,6 @@ files:
    description: "PS2, DTL-H50002 (v5.0 02/27/03 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "666018ffec65c5c7e04796081295c6c7"
    region_check: true
    fast_boot: Type2
@@ -806,7 +750,6 @@ files:
    description: "PS2, SCPH-50002/SCPH-50003/SCPH-50004 (v5.0 02/27/03 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "6e69920fa6eef8522a1d688a11e41bc6"
    region_check: true
    fast_boot: Type2
@@ -818,7 +761,6 @@ files:
    description: "PS2, DTL-H50001 (v5.0 03/25/03 A)"
    region: [north-america, latin-america]
    group: ps-bios
-    required: true
    md5: "eb960de68f0c0f7f9fa083e9f79d0360"
    region_check: true
    fast_boot: Type2
@@ -830,7 +772,6 @@ files:
    description: "PS2, SCPH-50001 (v5.0 03/25/03 A)"
    region: [north-america, latin-america]
    group: ps-bios
-    required: true
    md5: "8aa12ce243210128c5074552d3b86251"
    region_check: true
    fast_boot: Type2
@@ -842,7 +783,6 @@ files:
    description: "PS2, DTL-H50009 (v5.0 02/24/03 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "240d4c5ddd4b54069bdc4a3cd2faf99d"
    region_check: true
    fast_boot: Type2
@@ -854,7 +794,6 @@ files:
    description: "PS2, DESR-5000/DESR-5100/DESR-7000/DESR-7100 (v5.0 10/28/03 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "1c6cd089e6c83da618fbf2a081eb4888"
    region_check: true
    fast_boot: Type2
@@ -866,7 +805,6 @@ files:
    description: "PS2, SCPH-55000 (v5.0 06/23/03 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "463d87789c555a4a7604e97d7db545d1"
    region_check: true
    fast_boot: Type2
@@ -878,7 +816,6 @@ files:
    description: "PS2, DTL-H50001 (v5.0 06/23/03 A)"
    region: [north-america, latin-america]
    group: ps-bios
-    required: true
    md5: "ab9d49ad40ae49f19856ad187777b1b3"
    region_check: true
    fast_boot: Type2
@@ -890,7 +827,6 @@ files:
    description: "PS2, SCPH-50001/SCPH-50010 (v5.0 06/23/03 A)"
    region: [north-america, latin-america]
    group: ps-bios
-    required: true
    md5: "35461cecaa51712b300b2d6798825048"
    region_check: true
    fast_boot: Type2
@@ -902,7 +838,6 @@ files:
    description: "PS2, SCPH-50002/SCPH-50003/SCPH-50004 (v5.0 06/23/03 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "bd6415094e1ce9e05daabe85de807666"
    region_check: true
    fast_boot: Type2
@@ -914,7 +849,6 @@ files:
    description: "PS2, SCPH-50006/SCPH-50007 (v5.0 06/23/03 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "2e70ad008d4ec8549aada8002fdf42fb"
    region_check: true
    fast_boot: Type2
@@ -926,7 +860,6 @@ files:
    description: "PS2, SCPH-50005 (v5.0 06/23/03 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "50d5b97b57d8c9b6534adcb46c2027d4"
    region_check: true
    fast_boot: Type2
@@ -938,7 +871,6 @@ files:
    description: "PS2, SCPH-50008 (v5.0 06/23/03 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "b53d51edc7fc086685e31b811dc32aad"
    region_check: true
    fast_boot: Type2
@@ -950,7 +882,6 @@ files:
    description: "PS2, SCPH-50009 (v5.0 06/23/03 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "1b6e631b536247756287b916f9396872"
    region_check: true
    fast_boot: Type2
@@ -962,7 +893,6 @@ files:
    description: "PS2, SCPH-50000 (v5.0 08/22/03 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "00da1b177096cfd2532c8fa22b43e667"
    region_check: true
    fast_boot: Type2
@@ -974,7 +904,6 @@ files:
    description: "PS2, SCPH-50004 (v5.0 08/22/03 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "afde410bd026c16be605a1ae4bd651fd"
    region_check: true
    fast_boot: Type2
@@ -986,7 +915,6 @@ files:
    description: "PS2, SCPH-50011 (v5.0 03/29/04 A)"
    region: [north-america, latin-america]
    group: ps-bios
-    required: true
    md5: "81f4336c1de607dd0865011c0447052e"
    region_check: true
    fast_boot: Type2
@@ -998,7 +926,6 @@ files:
    description: "PS2, SCPH-70000 (v5.0 06/14/04 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "0eee5d1c779aa50e94edd168b4ebf42e"
    region_check: true
    fast_boot: Type2
@@ -1010,7 +937,6 @@ files:
    description: "PS2, SCPH-70001/SCPH-70011/SCPH-70012 (v5.0 06/14/04 A)"
    region: [north-america, latin-america]
    group: ps-bios
-    required: true
    md5: "d333558cc14561c1fdc334c75d5f37b7"
    region_check: true
    fast_boot: Type2
@@ -1022,7 +948,6 @@ files:
    description: "PS2, SCPH-70002/SCPH-70003/SCPH-70004/SCPH-70008 (v5.0 06/14/04 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "dc752f160044f2ed5fc1f4964db2a095"
    region_check: true
    fast_boot: Type2
@@ -1034,7 +959,6 @@ files:
    description: "PS2, SCPH-70002 (v5.0 06/14/04 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "7ebb4fc5eab6f79a27d76ac9aad392b2"
    region_check: true
    fast_boot: Type2
@@ -1046,7 +970,6 @@ files:
    description: "PS2, DTL-H70002 (v5.0 06/14/04 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "63ead1d74893bf7f36880af81f68a82d"
    region_check: true
    fast_boot: Type2
@@ -1058,7 +981,6 @@ files:
    description: "PS2, SCPH-70005/SCPH-70006/SCPH-70007 (v5.0 06/14/04 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "3e3e030c0f600442fa05b94f87a1e238"
    region_check: true
    fast_boot: Type2
@@ -1070,7 +992,6 @@ files:
    description: "PS2, DESR-5500/DESR-5700/DESR-7500/DESR-7700 (v5.0 09/17/04 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "1ad977bb539fc9448a08ab276a836bbc"
    region_check: true
    fast_boot: Type2
@@ -1082,7 +1003,6 @@ files:
    description: "PS2, DTL-H75000 (v5.0 06/20/05 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "bf0078ba5e19d57eae18047407f3b6e5"
    region_check: true
    fast_boot: Type2
@@ -1094,7 +1014,6 @@ files:
    description: "PS2, SCPH-75000 (v5.0 06/20/05 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "eb4f40fcf4911ede39c1bbfe91e7a89a"
    region_check: true
    fast_boot: Type2
@@ -1106,7 +1025,6 @@ files:
    description: "PS2, DTL-H75000A (v5.0 06/20/05 A)"
    region: [north-america, latin-america]
    group: ps-bios
-    required: true
    md5: "9959ad7a8685cad66206e7752ca23f8b"
    region_check: true
    fast_boot: Type2
@@ -1118,7 +1036,6 @@ files:
    description: "PS2, SCPH-75001/SCPH-75010 (v5.0 06/20/05 A)"
    region: [north-america, latin-america]
    group: ps-bios
-    required: true
    md5: "929a14baca1776b00869f983aa6e14d2"
    region_check: true
    fast_boot: Type2
@@ -1130,7 +1047,6 @@ files:
    description: "PS2, SCPH-75002/SCPH-75003/SCPH-75004/SCPH-75008 (v5.0 06/20/05 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "573f7d4a430c32b3cc0fd0c41e104bbd"
    region_check: true
    fast_boot: Type2
@@ -1142,7 +1058,6 @@ files:
    description: "PS2, SCPH-75006 (v5.0 06/20/05 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "df63a604e8bff5b0599bd1a6c2721bd0"
    region_check: true
    fast_boot: Type2
@@ -1154,7 +1069,6 @@ files:
    description: "PS2, SCPH-77000 (v5.0 02/10/06 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "5b1ba4bb914406fae75ab8e38901684d"
    region_check: true
    fast_boot: Type2
@@ -1166,7 +1080,6 @@ files:
    description: "PS2, SCPH-77001/SCPH-77010 (v5.0 02/10/06 A)"
    region: [north-america, latin-america]
    group: ps-bios
-    required: true
    md5: "cb801b7920a7d536ba07b6534d2433ca"
    region_check: true
    fast_boot: Type2
@@ -1178,7 +1091,6 @@ files:
    description: "PS2, SCPH-77002/SCPH-77003/SCPH-77004/SCPH-77008 (v5.0 02/10/06 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "af60e6d1a939019d55e5b330d24b1c25"
    region_check: true
    fast_boot: Type2
@@ -1190,7 +1102,6 @@ files:
    description: "PS2, SCPH-77006/SCPH-77007 (v5.0 02/10/06 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "549a66d0c698635ca9fa3ab012da7129"
    region_check: true
    fast_boot: Type2
@@ -1202,7 +1113,6 @@ files:
    description: "PS2, DTL-H90000 (v5.0 09/05/06 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "5e2014472c88f74f7547d8c2c60eca45"
    region_check: true
    fast_boot: Type2
@@ -1214,7 +1124,6 @@ files:
    description: "PS2, SCPH-79000/SCPH-90000 (v5.0 09/05/06 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "5de9d0d730ff1e7ad122806335332524"
    region_check: true
    fast_boot: Type2
@@ -1226,7 +1135,6 @@ files:
    description: "PS2, DTL-H90000 (v5.0 09/05/06 A)"
    region: [north-america, latin-america]
    group: ps-bios
-    required: true
    md5: "21fe4cad111f7dc0f9af29477057f88d"
    region_check: true
    fast_boot: Type2
@@ -1238,7 +1146,6 @@ files:
    description: "PS2, SCPH-79001/SCPH-79010/SCPH-90001 (v5.0 09/05/06 A)"
    region: [north-america, latin-america]
    group: ps-bios
-    required: true
    md5: "40c11c063b3b9409aa5e4058e984e30c"
    region_check: true
    fast_boot: Type2
@@ -1250,7 +1157,6 @@ files:
    description: "PS2, SCPH-79002/SCPH-79003/SCPH-79004/SCPH-79008/SCPH-90002/SCPH-90003/SCPH-90004 (v5.0 09/05/06 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "80bbb237a6af9c611df43b16b930b683"
    region_check: true
    fast_boot: Type2
@@ -1262,7 +1168,6 @@ files:
    description: "PS2, SCPH-79006/SCPH-79007/SCPH-90006/SCPH-90007 (v5.0 09/05/06 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "c37bce95d32b2be480f87dd32704e664"
    region_check: true
    fast_boot: Type2
@@ -1274,7 +1179,6 @@ files:
    description: "PS2, SCPH-90000 (v5.0 02/20/08 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "80ac46fa7e77b8ab4366e86948e54f83"
    region_check: true
    fast_boot: Type2
@@ -1286,7 +1190,6 @@ files:
    description: "PS2, SCPH-90001/SCPH-90010 (v5.0 02/20/08 A)"
    region: [north-america, latin-america]
    group: ps-bios
-    required: true
    md5: "21038400dc633070a78ad53090c53017"
    region_check: true
    fast_boot: Type2
@@ -1298,7 +1201,6 @@ files:
    description: "PS2, SCPH-90002/SCPH-90003/SCPH-90004/SCPH-90008 (v5.0 02/20/08 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "dc69f0643a3030aaa4797501b483d6c4"
    region_check: true
    fast_boot: Type2
@@ -1310,7 +1212,6 @@ files:
    description: "PS2, SCPH-90005/SCPH-90006/SCPH-90007 (v5.0 02/20/08 J)"
    region: [japan]
    group: ps-bios
-    required: true
    md5: "30d56e79d89fbddf10938fa67fe3f34e"
    region_check: true
    fast_boot: Type2
@@ -1322,7 +1223,6 @@ files:
    description: "PS2, KDL-22PX300 (v5.0 04/15/10 E)"
    region: [europe, oceania]
    group: ps-bios
-    required: true
    md5: "93ea3bcee4252627919175ff1b16a1d9"
    region_check: true
    fast_boot: Type2
@@ -1337,7 +1237,6 @@ files:
    description: "OpenBIOS"
    region: [world]
    group: ps-bios
-    required: true
    md5: null
    region_check: false
    fast_boot: unsupported
@@ -64,18 +64,23 @@ notes: |
  descent2 on install (scriptmodules/ports/dxx-rebirth.sh,
  game_data_dxx-rebirth).

+groups:
+  d1-hog:
+    required: true
+  d2-hog:
+    required: true
+
 files:
  # ------ Descent 1 shareware (free) ------
  - name: descent.hog
+    group: d1-hog
    installed_on: [retropie]
    path: descent.hog
    system: descent
    category: game_data
-    required: false
    size: 2339773
    validation: [size]
    description: "Descent 1 PC shareware v1.4 HOG"
-    variant_group: d1-hog
    note: "freely redistributable (icculus.org/d2x/data/desc14sw.tar.gz)"
    source_ref: "similar/main/mission.cpp:80; common/main/mission.h:67"

@@ -90,14 +95,13 @@ files:

  # ------ Descent 1 retail ------
  - name: descent.hog
+    group: d1-hog
    path: descent.hog
    system: descent
    category: game_data
-    required: false
    size: 6856701
    validation: [size]
    description: "Descent 1 PC retail v1.5 HOG (GOG)"
-    variant_group: d1-hog
    note: "commercial, alternative sizes 6856183 (v1.5 alt), 7261423 (v1.0), 7456179 (Mac retail)"
    source_ref: "common/main/mission.h:61-64"

@@ -111,15 +115,15 @@ files:

  # ------ Descent 2 shareware (free) ------
  - name: d2demo.hog
+    group: d2-hog
+    priority: 2
    installed_on: [retropie]
    path: d2demo.hog
    system: descent2
    category: game_data
-    required: false
    size: 2292566
    validation: [size]
    description: "Descent 2 PC shareware HOG"
-    variant_group: d2-hog
    note: "freely redistributable (icculus.org/d2x/data/d2shar10.tar.gz)"
    source_ref: "similar/main/mission.cpp:107-108; common/main/mission.h:71"

@@ -143,14 +147,14 @@ files:

  # ------ Descent 2 retail ------
  - name: descent2.hog
+    group: d2-hog
+    priority: 1
    path: descent2.hog
    system: descent2
    category: game_data
-    required: false
    size: 7595079
    validation: [size]
    description: "Descent 2 PC full v1.1-1.2 HOG (GOG)"
-    variant_group: d2-hog
    note: "commercial, alternative sizes 7107354 (v1.0), 7110007 (Mac full), 6132957 (OEM v1.1), 4292746 (Mac shareware)"
    source_ref: "common/main/mission.h:73-76"

@@ -133,13 +133,16 @@ notes: |
       ePSXe 2.0.18 Windows 0x4fb220-0x4fb263,
       DownloadShaderPluginTask.java:56-80

+groups:
+  ps-bios:
+    required: false
+
 files:
  - name: scph1000.bin
+    group: ps-bios
    path: bios/scph1000.bin
    system: sony-playstation
-    required: false
    hle_fallback: true
-    variant_group: "psx-bios"
    config_key: "BiosPath"
    size: 524288
    validation: [size, md5]
@@ -149,11 +152,10 @@ files:
    source_ref: "ScanBiosTask.java:28, ScanBiosTask.java:162-172, ePSXe 2.0.18 Windows 0x5c10b4"

  - name: scph1001.bin
+    group: ps-bios
    path: bios/scph1001.bin
    system: sony-playstation
-    required: false
    hle_fallback: true
-    variant_group: "psx-bios"
    config_key: "BiosPath"
    size: 524288
    validation: [size, md5]
@@ -163,11 +165,10 @@ files:
    source_ref: "ScanBiosTask.java:28, ePSXe 2.0.5 Linux x64 write_configfiledefault 0x42ae99, ePSXeReadPreferences.java:21, ePSXe 2.0.18 Windows 0x5c10d8"

  - name: scph1001_v20.bin
+    group: ps-bios
    path: bios/scph1001_v20.bin
    system: sony-playstation
-    required: false
    hle_fallback: true
-    variant_group: "psx-bios"
    config_key: "BiosPath"
    size: 524288
    validation: [size, md5]
@@ -177,11 +178,10 @@ files:
    source_ref: "ScanBiosTask.java:28, ePSXe 2.0.18 Windows 0x5c1120"

  - name: scph1002a.bin
+    group: ps-bios
    path: bios/scph1002a.bin
    system: sony-playstation
-    required: false
    hle_fallback: true
-    variant_group: "psx-bios"
    config_key: "BiosPath"
    size: 524288
    validation: [size, md5]
@@ -191,11 +191,10 @@ files:
    source_ref: "ScanBiosTask.java:28, ePSXe 2.0.18 Windows 0x5c10fc"

  - name: scph3000.bin
+    group: ps-bios
    path: bios/scph3000.bin
    system: sony-playstation
-    required: false
    hle_fallback: true
-    variant_group: "psx-bios"
    config_key: "BiosPath"
    size: 524288
    validation: [size, md5]
@@ -205,11 +204,10 @@ files:
    source_ref: "ScanBiosTask.java:28, ePSXe 2.0.18 Windows 0x5c1144"

  - name: scph3500.bin
+    group: ps-bios
    path: bios/scph3500.bin
    system: sony-playstation
-    required: false
    hle_fallback: true
-    variant_group: "psx-bios"
    config_key: "BiosPath"
    size: 524288
    validation: [size, md5]
@@ -219,11 +217,10 @@ files:
    source_ref: "ScanBiosTask.java:28, ePSXe 2.0.18 Windows 0x5c1168"

  - name: dtlh1100.bin
+    group: ps-bios
    path: bios/dtlh1100.bin
    system: sony-playstation
-    required: false
    hle_fallback: true
-    variant_group: "psx-bios"
    config_key: "biosPref"
    size: 524288
    validation: [size, md5]
@@ -233,11 +230,10 @@ files:
    source_ref: "ScanBiosTask.java:28, ScanBiosTask.java:162-172"

  - name: scph1001_v21.bin
+    group: ps-bios
    path: bios/scph1001_v21.bin
    system: sony-playstation
-    required: false
    hle_fallback: true
-    variant_group: "psx-bios"
    config_key: "biosPref"
    size: 524288
    validation: [size, md5]
@@ -247,11 +243,10 @@ files:
    source_ref: "ScanBiosTask.java:28, ScanBiosTask.java:162-172"

  - name: scph1002b.bin
+    group: ps-bios
    path: bios/scph1002b.bin
    system: sony-playstation
-    required: false
    hle_fallback: true
-    variant_group: "psx-bios"
    config_key: "biosPref"
    size: 524288
    validation: [size, md5]
@@ -261,11 +256,10 @@ files:
    source_ref: "ScanBiosTask.java:28, ScanBiosTask.java:162-172"

  - name: scph5000.bin
+    group: ps-bios
    path: bios/scph5000.bin
    system: sony-playstation
-    required: false
    hle_fallback: true
-    variant_group: "psx-bios"
    config_key: "biosPref"
    size: 524288
    validation: [size, md5]
@@ -275,11 +269,10 @@ files:
    source_ref: "ScanBiosTask.java:28, ScanBiosTask.java:162-172"

  - name: scph1002c.bin
+    group: ps-bios
    path: bios/scph1002c.bin
    system: sony-playstation
-    required: false
    hle_fallback: true
-    variant_group: "psx-bios"
    config_key: "BiosPath"
    size: 524288
    validation: [size, md5]
@@ -289,11 +282,10 @@ files:
    source_ref: "ScanBiosTask.java:28, ePSXe 2.0.18 Windows 0x5c1090"

  - name: scph5500.bin
+    group: ps-bios
    path: bios/scph5500.bin
    system: sony-playstation
-    required: false
    hle_fallback: true
-    variant_group: "psx-bios"
    config_key: "BiosPath"
    size: 524288
    validation: [size, md5]
@@ -303,11 +295,10 @@ files:
    source_ref: "ScanBiosTask.java:28, ePSXe 2.0.18 Windows 0x5c11b0"

  - name: scph5501.bin
+    group: ps-bios
    path: bios/scph5501.bin
    system: sony-playstation
-    required: false
    hle_fallback: true
-    variant_group: "psx-bios"
    config_key: "BiosPath"
    size: 524288
    validation: [size, md5]
@@ -317,11 +308,10 @@ files:
    source_ref: "ScanBiosTask.java:28, ePSXe 2.0.18 Windows 0x5c1288"

  - name: scph5502.bin
+    group: ps-bios
    path: bios/scph5502.bin
    system: sony-playstation
-    required: false
    hle_fallback: true
-    variant_group: "psx-bios"
    config_key: "BiosPath"
    size: 524288
    validation: [size, md5]
@@ -331,11 +321,10 @@ files:
    source_ref: "ScanBiosTask.java:28, ePSXe 2.0.18 Windows 0x5c11f8"

  - name: scph7000.bin
+    group: ps-bios
    path: bios/scph7000.bin
    system: sony-playstation
-    required: false
    hle_fallback: true
-    variant_group: "psx-bios"
    config_key: "BiosPath"
    size: 524288
    validation: [size, md5]
@@ -345,11 +334,10 @@ files:
    source_ref: "ScanBiosTask.java:28, ePSXe 2.0.18 Windows 0x5c121c"

  - name: scph7001.bin
+    group: ps-bios
    path: bios/scph7001.bin
    system: sony-playstation
-    required: false
    hle_fallback: true
-    variant_group: "psx-bios"
    config_key: "BiosPath"
    size: 524288
    validation: [size, md5]
@@ -359,11 +347,10 @@ files:
    source_ref: "ScanBiosTask.java:28, ePSXe 2.0.18 Windows 0x5c1240"

  - name: scph7002.bin
+    group: ps-bios
    path: bios/scph7002.bin
    system: sony-playstation
-    required: false
    hle_fallback: true
-    variant_group: "psx-bios"
    config_key: "BiosPath"
    size: 524288
    validation: [size, md5]
@@ -373,11 +360,10 @@ files:
    source_ref: "ScanBiosTask.java:28, ePSXe 2.0.18 Windows 0x5c1264, ePSXe 2.0.18 Windows 0x5c12ac, ePSXe 2.0.18 Windows 0x5c12d0"

  - name: scph100.bin
+    group: ps-bios
    path: bios/scph100.bin
    system: sony-playstation
-    required: false
    hle_fallback: true
-    variant_group: "psx-bios"
    config_key: "BiosPath"
    size: 524288
    validation: [size, md5]
@@ -387,11 +373,10 @@ files:
    source_ref: "ScanBiosTask.java:28, ePSXe 2.0.18 Windows 0x5c12f4"

  - name: scph102_v44.bin
+    group: ps-bios
    path: bios/scph102_v44.bin
    system: sony-playstation
-    required: false
    hle_fallback: true
-    variant_group: "psx-bios"
    config_key: "BiosPath"
    size: 524288
    validation: [size, md5]
@@ -401,11 +386,10 @@ files:
    source_ref: "ScanBiosTask.java:28, ePSXe 2.0.18 Windows 0x5c133c"

  - name: scph101_v45.bin
+    group: ps-bios
    path: bios/scph101_v45.bin
    system: sony-playstation
-    required: false
    hle_fallback: true
-    variant_group: "psx-bios"
    config_key: "BiosPath"
    size: 524288
    validation: [size, md5]
@@ -415,11 +399,10 @@ files:
    source_ref: "ScanBiosTask.java:28, ePSXe 2.0.18 Windows 0x5c1318"

  - name: scph102_v45.bin
+    group: ps-bios
    path: bios/scph102_v45.bin
    system: sony-playstation
-    required: false
    hle_fallback: true
-    variant_group: "psx-bios"
    config_key: "BiosPath"
    size: 524288
    validation: [size, md5]
@@ -429,11 +412,10 @@ files:
    source_ref: "ScanBiosTask.java:28, ePSXe 2.0.18 Windows 0x5c1360"

  - name: scph5000_b.bin
+    group: ps-bios
    path: bios/scph5000_b.bin
    system: sony-playstation
-    required: false
    hle_fallback: true
-    variant_group: "psx-bios"
    config_key: "BiosPath"
    size: 524288
    validation: [size]
@@ -443,11 +425,10 @@ files:
    source_ref: "ePSXe 2.0.18 Windows 0x5c118c, ePSXe 2.0.18 Windows 0x42f525-0x42f568"

  - name: scph5502_b.bin
+    group: ps-bios
    path: bios/scph5502_b.bin
    system: sony-playstation
-    required: false
    hle_fallback: true
-    variant_group: "psx-bios"
    config_key: "BiosPath"
    size: 524288
    validation: [size]
@@ -133,13 +133,16 @@ notes: |
       Main.java:11014, Main.java:12555-12585, Main.java:15415-15430,
       Main.java:15489

+groups:
+  ps-bios:
+    required: false
+
 files:
  - name: scph1001.bin
+    group: ps-bios
    path: bios/scph1001.bin
    system: sony-playstation
-    required: false
    hle_fallback: true
-    variant_group: "psx-bios"
    config_key: "com.emulator.fpse64.biospath"
    size: 524288
    validation: [size]
@@ -105,13 +105,16 @@ notes: |
  ref: Main.java:26892-26895, Main.java:26956-26957, Main.java:29721,
       Main.java:29755-29758, Main.java:30046

+groups:
+  ps-bios:
+    required: false
+
 files:
  - name: scph1001.bin
+    group: ps-bios
    path: bios/scph1001.bin
    system: sony-playstation
-    required: false
    hle_fallback: true
-    variant_group: "psx-bios"
    config_key: "BiosName"
    size: 524288
    validation: [size]
@@ -37,12 +37,15 @@ notes: |
  The .info file declares all three firmware files as required (opt=false),
  but the core does not abort on a missing BIOS. It falls back to HLE.

+groups:
+  psu1:
+    required: false
+
 files:
  - name: "sl31253.bin"
    system: fairchild-channelf
    group: psu1
    priority: 2
-    required: false
    hle_fallback: true
    note: "Channel F PSU1 ROM (original). Fallback if sl90025.bin is missing."
    source_ref: "src/libretro.c:192"
@@ -58,7 +61,6 @@ files:
    system: fairchild-channelf
    group: psu1
    priority: 1
-    required: false
    hle_fallback: true
    note: "Channel F II PSU1 ROM. Tried first, preferred over sl31253.bin."
    source_ref: "src/libretro.c:186"
@@ -48,6 +48,10 @@ notes: |

 archive_prefix: kronos

+groups:
+  saturn-bios:
+    required: true
+
 files:
  # -----------------------------------------------------------
  # Saturn BIOS - primary (any region)
@@ -57,7 +61,6 @@ files:
    system: sega-saturn
    group: saturn-bios
    priority: 1
-    required: true
    size: 524288
    validation: [size]
    note: "Primary Saturn BIOS. Any region accepted. Searched in kronos/ subdir first."
@@ -67,7 +70,6 @@ files:
    system: sega-saturn
    group: saturn-bios
    priority: 2
-    required: true
    size: 524288
    validation: [size]
    note: "The same name in the system directory, read when kronos/ holds none."
@@ -80,7 +82,6 @@ files:
    system: sega-saturn
    group: saturn-bios
    priority: 3
-    required: true
    size: 524288
    validation: [size]
    note: "Saturn BIOS v1.01 (Japan). Fallback if saturn_bios.bin missing."
@@ -93,7 +94,6 @@ files:
    system: sega-saturn
    group: saturn-bios
    priority: 4
-    required: true
    size: 524288
    validation: [size]
    note: "Saturn BIOS (NA/EU). Last fallback for Saturn mode."
@@ -39,13 +39,16 @@ notes: |
  underlying engine (calc.cpp:rom_load) auto-detects the model from the ROM
  header.

+groups:
+  rom:
+    required: true
+
 files:
  - name: "ti83se.rom"
    system: ti-83
    description: "TI-83 Plus Silver Edition ROM dump"
    group: rom
    priority: 1
-    required: true
    source_ref: "source libnumero/libretro/libretronew.cpp:576-578"
    note: "Checked first. Recommended for largest storage capacity."

@@ -54,7 +57,6 @@ files:
    description: "TI-83 Plus ROM dump"
    group: rom
    priority: 2
-    required: true
    source_ref: "source libnumero/libretro/libretronew.cpp:583-585"
    note: "Checked second, used if ti83se.rom is missing."

@@ -63,6 +65,5 @@ files:
    description: "TI-83 ROM dump"
    group: rom
    priority: 3
-    required: true
    source_ref: "source libnumero/libretro/libretronew.cpp:591-593"
    note: "Checked last. Original TI-83 (non-Plus)."
@@ -41,7 +41,7 @@ files:
  - name: "o2rom.bin"
    system: odyssey2
    required: true
-    variant_group: "o2em-bios"
+    selection_slot: "o2em-bios"
    min_size: 1024
    md5: "562d5ebf9e030a40d6fabfc2f33139fd"
    sha1: "b2e1955d957a475de2411770452eff4ea19f4cee"
@@ -57,7 +57,7 @@ files:
  - name: "c52.bin"
    system: videopac
    required: false
-    variant_group: "o2em-bios"
+    selection_slot: "o2em-bios"
    min_size: 1024
    md5: "f1071cdb0b6b10dde94d3bc8a6146387"
    sha1: "a6120aed50831c9c0d95dbdf707820f601d9452e"
@@ -69,7 +69,7 @@ files:
  - name: "g7400.bin"
    system: videopac
    required: false
-    variant_group: "o2em-bios"
+    selection_slot: "o2em-bios"
    min_size: 1024
    md5: "c500ff71236068e0dc0d0603d265ae76"
    sha1: "5130243429b40b01a14e1304d0394b8459a6fbae"
@@ -81,7 +81,7 @@ files:
  - name: "jopac.bin"
    system: videopac
    required: false
-    variant_group: "o2em-bios"
+    selection_slot: "o2em-bios"
    min_size: 1024
    md5: "279008e4a0db2dc5f1c048853b033828"
    sha1: "54b8d2c1317628de51a85fc1c424423a986775e4"
@@ -71,6 +71,10 @@ notes: |

 archive_prefix: "odin"

+groups:
+  boot-rom:
+    required: true
+
 files:
  - name: "hikaru.zip"
    path: "odin/hikaru.zip"
@@ -84,8 +88,6 @@ files:
    archive: hikaru.zip
    system: sega-hikaru
    group: boot-rom
-    required: true
-    variant_group: "hikaru-bootrom"
    priority: 1
    size: 2097152
    crc32: "2aa906a7"
@@ -97,8 +99,6 @@ files:
    archive: hikaru.zip
    system: sega-hikaru
    group: boot-rom
-    required: true
-    variant_group: "hikaru-bootrom"
    priority: 2
    size: 2097152
    crc32: "3d557104"
@@ -110,8 +110,6 @@ files:
    archive: hikaru.zip
    system: sega-hikaru
    group: boot-rom
-    required: true
-    variant_group: "hikaru-bootrom"
    priority: 3
    size: 2097152
    crc32: "d96298b6"
@@ -22,12 +22,15 @@ notes: >
  No region detection, no hash validation. First valid BIOS found is used regardless of region.
  .info declares scph5500/5501/5502 but code explicitly searches scph1001/5501/7001 first.

+groups:
+  bios:
+    required: false
+
 files:
  - name: "scph1001.bin"
    description: "SCPH-1001 (v2.2 12-04-95 A)"
    group: bios
    priority: 1
-    required: false
    hle_fallback: true
    size: 524288
    validation: [size]
@@ -40,7 +43,6 @@ files:
    description: "SCPH-5501 (v3.0 11-18-96 A)"
    group: bios
    priority: 2
-    required: false
    hle_fallback: true
    size: 524288
    validation: [size]
@@ -53,7 +55,6 @@ files:
    description: "SCPH-7001 (v4.1 12-16-97 A)"
    group: bios
    priority: 3
-    required: false
    hle_fallback: true
    size: 524288
    validation: [size]
@@ -55,6 +55,14 @@ notes: |
  initializes VDP registers and RAM to simulate post-BIOS state
  (pico/sms.c:1080-1097).

+groups:
+  mega-cd-us:
+    required: true
+  mega-cd-eu:
+    required: true
+  mega-cd-jp:
+    required: true
+
 files:
  # -------------------------------------------------------
  # Cartridge hardware database
@@ -69,44 +77,40 @@ files:
  # -------------------------------------------------------
  - name: "us_scd2_9306.bin"
    system: sega-megacd
-    variant_group: "mega-cd-bios"
+    selection_slot: "mega-cd-bios"
    region: [north-america, latin-america]
    group: mega-cd-us
    priority: 1
-    required: true
    size: 131072  # 128 KB (0x20000)
    note: "US Sega CD Model 2 BIOS (September 1993). First in US search order. The US list serves every disc whose security byte is neither 0x64 nor 0xa1 (pico/cd/cd_image.c:190, 247-248)."
    source_ref: "source platform/libretro/libretro.c:1273"

  - name: "SegaCDBIOS9303.bin"
    system: sega-megacd
-    variant_group: "mega-cd-bios"
+    selection_slot: "mega-cd-bios"
    region: [north-america, latin-america]
    group: mega-cd-us
    priority: 2
-    required: true
    size: 131072
    note: "US Sega CD BIOS (March 1993). Second in US search order."
    source_ref: "source platform/libretro/libretro.c:1273"

  - name: "us_scd1_9210.bin"
    system: sega-megacd
-    variant_group: "mega-cd-bios"
+    selection_slot: "mega-cd-bios"
    region: [north-america, latin-america]
    group: mega-cd-us
    priority: 3
-    required: true
    size: 131072
    note: "US Sega CD Model 1 BIOS (October 1992). Third in US search order."
    source_ref: "source platform/libretro/libretro.c:1273"

  - name: "bios_CD_U.bin"
    system: sega-megacd
-    variant_group: "mega-cd-bios"
+    selection_slot: "mega-cd-bios"
    region: [north-america, latin-america]
    group: mega-cd-us
    priority: 4
-    required: true
    size: 131072
    note: "US Sega CD BIOS (generic name). Last in US search order."
    source_ref: "source platform/libretro/libretro.c:1273"
@@ -116,44 +120,40 @@ files:
  # -------------------------------------------------------
  - name: "eu_mcd2_9306.bin"
    system: sega-megacd
-    variant_group: "mega-cd-bios"
+    selection_slot: "mega-cd-bios"
    region: [europe, oceania]
    group: mega-cd-eu
    priority: 1
-    required: true
    size: 131072
    note: "EU Mega CD Model 2 BIOS (June 1993). First in EU search order, used when security byte 0x20b is 0x64, the only PAL branch for Australian discs (pico/media.c:243-247, platform/libretro/libretro.c:1306-1308)."
    source_ref: "source platform/libretro/libretro.c:1276"

  - name: "eu_mcd2_9303.bin"
    system: sega-megacd
-    variant_group: "mega-cd-bios"
+    selection_slot: "mega-cd-bios"
    region: [europe, oceania]
    group: mega-cd-eu
    priority: 2
-    required: true
    size: 131072
    note: "EU Mega CD Model 2 BIOS (March 1993). Second in EU search order."
    source_ref: "source platform/libretro/libretro.c:1276"

  - name: "eu_mcd1_9210.bin"
    system: sega-megacd
-    variant_group: "mega-cd-bios"
+    selection_slot: "mega-cd-bios"
    region: [europe, oceania]
    group: mega-cd-eu
    priority: 3
-    required: true
    size: 131072
    note: "EU Mega CD Model 1 BIOS (October 1992). Third in EU search order."
    source_ref: "source platform/libretro/libretro.c:1276"

  - name: "bios_CD_E.bin"
    system: sega-megacd
-    variant_group: "mega-cd-bios"
+    selection_slot: "mega-cd-bios"
    region: [europe, oceania]
    group: mega-cd-eu
    priority: 4
-    required: true
    size: 131072
    note: "EU Mega CD BIOS (generic name). Last in EU search order."
    source_ref: "source platform/libretro/libretro.c:1276"
@@ -163,44 +163,40 @@ files:
  # -------------------------------------------------------
  - name: "jp_mcd2_921222.bin"
    system: sega-megacd
-    variant_group: "mega-cd-bios"
+    selection_slot: "mega-cd-bios"
    region: [japan]
    group: mega-cd-jp
    priority: 1
-    required: true
    size: 131072
    note: "JP Mega CD Model 2 BIOS (December 1992). First in JP search order."
    source_ref: "source platform/libretro/libretro.c:1279"

  - name: "jp_mcd1_9112.bin"
    system: sega-megacd
-    variant_group: "mega-cd-bios"
+    selection_slot: "mega-cd-bios"
    region: [japan]
    group: mega-cd-jp
    priority: 2
-    required: true
    size: 131072
    note: "JP Mega CD Model 1 BIOS (December 1991). Second in JP search order."
    source_ref: "source platform/libretro/libretro.c:1279"

  - name: "jp_mcd1_9111.bin"
    system: sega-megacd
-    variant_group: "mega-cd-bios"
+    selection_slot: "mega-cd-bios"
    region: [japan]
    group: mega-cd-jp
    priority: 3
-    required: true
    size: 131072
    note: "JP Mega CD Model 1 BIOS (November 1991). Third in JP search order."
    source_ref: "source platform/libretro/libretro.c:1279"

  - name: "bios_CD_J.bin"
    system: sega-megacd
-    variant_group: "mega-cd-bios"
+    selection_slot: "mega-cd-bios"
    region: [japan]
    group: mega-cd-jp
    priority: 4
-    required: true
    size: 131072
    note: "JP Mega CD BIOS (generic name). Last in JP search order."
    source_ref: "source platform/libretro/libretro.c:1279"
@@ -90,7 +90,7 @@ files:
    system: sega-megacd
    required: true
    agnostic: true
-    variant_group: "megacd-boot-rom"
+    selection_slot: "megacd-boot-rom"
    size: 131072
    validation: [size]
    description: "Sega CD boot ROM"
@@ -116,7 +116,7 @@ files:
    system: sega-megacd
    required: true
    agnostic: true
-    variant_group: "megacd-boot-rom"
+    selection_slot: "megacd-boot-rom"
    size: 131072
    validation: [size]
    description: "Mega CD boot ROM"
@@ -129,7 +129,7 @@ files:
    system: sega-megacd
    required: true
    agnostic: true
-    variant_group: "megacd-boot-rom"
+    selection_slot: "megacd-boot-rom"
    size: 131072
    validation: [size]
    description: "Mega CD boot ROM (Japan)"
@@ -142,7 +142,7 @@ files:
    system: sega-mastersystem
    required: false
    agnostic: true
-    variant_group: "mastersystem-boot-rom"
+    selection_slot: "mastersystem-boot-rom"
    description: "Master System boot ROM"
    note: >-
      Picked and stored like the Mega CD image and handed to the machine as a path.
@@ -157,7 +157,7 @@ files:
    system: sega-mastersystem
    required: false
    agnostic: true
-    variant_group: "mastersystem-boot-rom"
+    selection_slot: "mastersystem-boot-rom"
    description: "Master System boot ROM (Europe)"
    note: "Same slot and same absence of tests as the other Master System boot ROMs."
    source_ref: "Pizza Boy SC Basic 1.2.14 libsc.so frontend/android/src/lib.rs:590,
@@ -167,7 +167,7 @@ files:
    system: sega-mastersystem
    required: false
    agnostic: true
-    variant_group: "mastersystem-boot-rom"
+    selection_slot: "mastersystem-boot-rom"
    description: "Master System boot ROM (Japan)"
    note: "Same slot and same absence of tests as the other Master System boot ROMs."
    source_ref: "Pizza Boy SC Basic 1.2.14 libsc.so frontend/android/src/lib.rs:590,
@@ -61,8 +61,10 @@ notes: |
    //c             apple2c-32Kv0.rom, apple2c-16K.rom, 3420033a.256
    //c Plus        apple2cp.rom, apple2c-plus.rom, apple2c-32Kv0.rom
  With no candidate the machine runs on a $D000-$FFFF stub and the Welcome
-  panel opens (src/MainWindow.cpp:357-364). A first run with no //e image
-  falls back to the ][+ chain (src/MainWindow.cpp:246-259).
+  panel opens (src/MainWindow.cpp:357-364). A first run boots the //e on
+  apple2e.rom, else the ][+ chain, else the //c chain
+  (src/MainWindow.cpp:246-296): one of these is the set the machine needs,
+  each model's chain is a set of its own.
  Memory::loadAppleIIRom (src/Memory.cpp:177-264) maps 12 KB at $D000,
  16 KB at $C000, skips the 4 KB pad of a 20 KB ][+ dump, and slices a
  32 KB dump by profile: //e images carry the firmware in the upper half,
@@ -190,13 +192,32 @@ notes: |
  browsed from disks_5.4/, disks_3.5/, hdv/, floppyemu/, bundled_disks/,
  cassettes/ and prodos_folder/ next to the executable.

+groups:
+  boot:
+    required: true
+  ii:
+    required: false
+  ii-plus:
+    required: false
+  iie-unenhanced:
+    required: false
+  iic:
+    required: false
+  iic-plus:
+    required: false
+  char:
+    required: false
+  char-iie-unenhanced:
+    required: false
+  videoterm:
+    required: false
+
 files:
  - name: "apple2o.rom"
    path: "roms/apple2o.rom"
+    group: {ii: 1}
    description: "Apple ][ Original monitor and Integer BASIC, $D000-$FFFF"
-    required: false
    bundled: false
-    priority: 1
    size: 12288
    sha256: "68d9db6bb4c305d40c3fa89fa0f2d7b7f71516a9431e3138859f23bc5bddb2d1"
    sha1: "78008be557f643e956a106121bcc182c0fb9ea6d"
@@ -205,10 +226,9 @@ files:
    note: "First candidate of the Apple ][ Original profile. apple2.rom is probed next."
  - name: "apple2.rom"
    path: "roms/apple2.rom"
+    group: {ii: 2, ii-plus: 2, boot: 3}
    description: "Apple ][ generic 12 KB fallback, Autostart monitor and Applesoft"
-    required: false
    bundled: false
-    priority: 2
    size: 12288
    sha256: "fc3e9d41e9428534a883df5aa10eb55b73ea53d2fcbb3ee4f39bed1b07a82905"
    sha1: "33a24f5489ba9195b44be77d9afb2252594cb5c7"
@@ -217,10 +237,9 @@ files:
    note: "Probed after the profile image for the ][ and ][+ profiles. When it resolves in place of that image the loader logs that the ROM identity may not match the machine."
  - name: "apple2p.rom"
    path: "roms/apple2p.rom"
+    group: {ii-plus: 1, boot: 2}
    description: "Apple ][+ Autostart monitor and Applesoft, 4 KB pad then $C000-$FFFF"
-    required: false
    bundled: false
-    priority: 1
    size: [12288, 20480]
    sha256: "92c4bef609920842ea472d21b661a0d35dbda6cd90963b8b734a205e22d84108"
    sha1: "29a53f3bb158b160433369e8e4a1d7cd5bf68ac6"
@@ -229,10 +248,9 @@ files:
    note: "First candidate of the ][+ profile and of the first-run fallback (src/MainWindow.cpp:255-259). The loader drops the leading 4 KB of the 20 KB dump. The fetch gate names that dump, but a 12 KB six-chip image already on disk is kept as present without a digest check."
  - name: "apple2e.rom"
    path: "roms/apple2e.rom"
+    group: {boot: 1, iie-unenhanced: 3}
    description: "Apple //e Enhanced firmware, 32 KB dump with the 16 KB firmware in the upper half"
-    required: true
    bundled: false
-    priority: 1
    size: 32768
    sha256: "c17bc38c75ba96c33a30c688a1efd60144811073423533fe7f8453cdd9457aab"
    sha1: "d756eba578a6c5a4807510dfee30ee585c63755e"
@@ -241,10 +259,9 @@ files:
    note: "Sole candidate of the //e Enhanced profiles, NTSC and PAL, PAL being the default machine. Also the last fallback of the //e Unenhanced chain."
  - name: "apple2e_unenh.rom"
    path: "roms/apple2e_unenh.rom"
+    group: {iie-unenhanced: 1}
    description: "Apple //e Unenhanced firmware, 4 KB internal $Cx00 ROM then $D000-$FFFF"
-    required: false
    bundled: false
-    priority: 1
    aliases: ["342-0135-b.64.rom"]
    size: 16384
    sha256: "1fb812584c6633fa16b77b20915986ed1178d1e6fc07a647f7ee8d4e6ab9d40b"
@@ -254,10 +271,9 @@ files:
    note: "First candidate of the //e Unenhanced profiles. 342-0135-b.64.rom is probed second, apple2e.rom third. The fetcher assembles it from the two 8 KB chips of the MAME apple2e set, 342-0135-b.64 then 342-0134-a.64."
  - name: "apple2c-32Kv0.rom"
    path: "roms/apple2c-32Kv0.rom"
+    group: {iic: 1, iic-plus: 3, boot: 4}
    description: "Apple //c two-bank firmware, bank 0 in the lower 16 KB"
-    required: false
    bundled: false
-    priority: 1
    size: 32768
    crc32: "323952d1"
    sha256: "d65bbf97058b9cdce8eaebf74124048e3b4e42dca1bd42be316747bbc27dc124"
@@ -267,10 +283,9 @@ files:
    note: "First candidate of the //c and //c PAL profiles, third of the //c Plus chain. Bank 0 is mapped at reset, the $C028 ROMBANK switch selects the other. Identical to 3420033a.256 with its first 256 bytes zeroed."
  - name: "apple2c-16K.rom"
    path: "roms/apple2c-16K.rom"
+    group: {iic: 2, boot: 5}
    description: "Apple //c ROM 255, 16 KB, MAME apple2c a2c.128"
-    required: false
    bundled: false
-    priority: 2
    size: 16384
    crc32: "f0edaa1b"
    sha256: "3ca1c8a27bf111aa0f4dc9372c5e6404457adb9a458ce32ae4b03a7e989e0c76"
@@ -280,10 +295,9 @@ files:
    note: "Second candidate of the //c chain, loaded at $C000."
  - name: "3420033a.256"
    path: "roms/3420033a.256"
+    group: {iic: 3, boot: 6}
    description: "Apple //c ROM 0, UniDisk 3.5 firmware, MAME apple2c0 342-0033-A"
-    required: false
    bundled: false
-    priority: 3
    size: 32768
    crc32: "c8b979b3"
    sha256: "678d5c9d374664d2ee94ba9c9564d26a917b31116b07c46df30a3e82c640885b"
@@ -293,10 +307,9 @@ files:
    note: "Third candidate of the //c chain."
  - name: "apple2cp.rom"
    path: "roms/apple2cp.rom"
+    group: {iic-plus: 1}
    description: "Apple //c Plus two-bank firmware, MAME apple2cp 341-0625-a.256"
-    required: false
    bundled: false
-    priority: 1
    aliases: ["apple2c-plus.rom"]
    size: 32768
    crc32: "0b996420"
@@ -307,10 +320,9 @@ files:
    note: "First candidate of the //c Plus profile. apple2c-plus.rom is probed second and apple2c-32Kv0.rom third."
  - name: "apple2_char.rom"
    path: "roms/apple2_char.rom"
+    group: {char: 2, char-iie-unenhanced: 3}
    description: "Apple ][ and ][+ character generator, 2 KB uppercase set"
-    required: false
    bundled: false
-    priority: 1
    size: 2048
    sha256: "08f5d22230481019844492dde0a29a018cb193712a9e4a43770a3870608f28de"
    sha1: "f9d312f128c9557d9d6ac03bfad6c3ddf83e5659"
@@ -319,10 +331,9 @@ files:
    note: "Sole candidate of the ][ and ][+ profiles and the last fallback of every //e-class chain."
  - name: "apple2e_char.rom"
    path: "roms/apple2e_char.rom"
+    group: {char: 1}
    description: "Apple //e Enhanced character generator 342-0265-A, 4 KB with MouseText"
-    required: false
    bundled: false
-    priority: 1
    aliases: ["apple2e_char_us.rom"]
    size: 4096
    sha256: "52c3b87900ac939f6525402cab1ccfd8f8259290fc6df54da48fb4c98ae3ed0f"
@@ -332,10 +343,9 @@ files:
    note: "First candidate of the //e Enhanced, //c and //c Plus profiles. The same dump answers to apple2e_char_us.rom in the locale picker, and the fetcher writes both names."
  - name: "apple2e_char_us_unenh.rom"
    path: "roms/apple2e_char_us_unenh.rom"
+    group: {char-iie-unenhanced: 1}
    description: "Apple //e Unenhanced character generator 342-0133-A, 4 KB"
-    required: false
    bundled: false
-    priority: 1
    aliases: ["apple2e_char_2k.rom", "342-0133-a.chr.rom"]
    size: 4096
    sha256: "ed5bdd4afa509134e85f1d020685af7ff50e279226eb869a17825b471cc1634c"
@@ -629,9 +639,8 @@ files:
    note: "The Apple Parallel Interface leaves its slot empty without it. The fetcher extracts it from the MAME a2pic set as 341-0057.7b."
  - name: "videx_videoterm_v24_60hz.bin"
    path: "roms/videx_videoterm_v24_60hz.bin"
+    group: {videoterm: 1}
    description: "Videx Videoterm firmware v2.4 with the 60 Hz CRTC table, 2 KB, MAME a2videoterm 6.ic6.bin"
-    required: false
-    priority: 1
    size: 2048
    crc32: "5776fa24"
    sha256: "420da3867e489824f5fc0377c287c48a125296f19e1306df764e8f63bd23b00a"
@@ -641,9 +650,8 @@ files:
    note: "First firmware candidate of the Videoterm card. The 50 Hz dump is probed second. With neither the slot stays empty. The fetcher extracts it from the MAME a2vidtrm set."
  - name: "videx_videoterm_v24_50hz.bin"
    path: "roms/videx_videoterm_v24_50hz.bin"
+    group: {videoterm: 2}
    description: "Videx Videoterm firmware v2.4 with the 50 Hz CRTC table, 1 KB, MAME a2videoterm videx videoterm rom 2.4.bin"
-    required: false
-    priority: 2
    size: 1024
    crc32: "bbe3bb28"
    sha256: "616f4d9f81a7a4ea0fa918842a05dfb3b503927776d2bfe97e6950b5431b562e"
@@ -47,13 +47,18 @@ notes: |
  General MIDI SoundFont works. The Mercury unit is compiled out
  (Makefile:120-123).

+groups:
+  ipl:
+    required: true
+  font:
+    required: true
+
 files:
  - name: "iplrom.dat"
    system: sharp-x68000
    path: "iplrom.dat"
    group: ipl
    priority: 1
-    required: true
    size: 131072
    source_ref: "SDL/SDL2/winx68k.cpp:277-279,288-307"
    note: >
@@ -67,7 +72,6 @@ files:
    path: "iplromxv.dat"
    group: ipl
    priority: 2
-    required: true
    size: 131072
    source_ref: "SDL/SDL2/winx68k.cpp:277-279,288-307"
    note: "X68000 XVI IPL ROM, read when iplrom.dat is absent."
@@ -77,7 +81,6 @@ files:
    path: "iplromco.dat"
    group: ipl
    priority: 3
-    required: true
    size: 131072
    source_ref: "SDL/SDL2/winx68k.cpp:277-279,288-307"
    note: "X68000 Compact IPL ROM, read when the first two names are absent."
@@ -87,7 +90,6 @@ files:
    path: "iplrom30.dat"
    group: ipl
    priority: 4
-    required: true
    size: 131072
    source_ref: "SDL/SDL2/winx68k.cpp:277-279,288-307"
    note: "X68030 IPL ROM, read when the three other names are absent."
@@ -97,7 +99,6 @@ files:
    path: "cgrom30.dat"
    group: font
    priority: 1
-    required: true
    size: 786432
    source_ref: "SDL/SDL2/winx68k.cpp:280-282,317-331"
    note: >
@@ -110,7 +111,6 @@ files:
    path: "cgrom30.tmp"
    group: font
    priority: 2
-    required: true
    unsourceable: "rendered from TrueType fonts by the font generator, no canonical file"
    size: 786432
    source_ref: "SDL/SDL2/winx68k.cpp:280-282,317-331"
@@ -121,7 +121,6 @@ files:
    path: "cgrom.dat"
    group: font
    priority: 3
-    required: true
    size: 786432
    source_ref: "SDL/SDL2/winx68k.cpp:280-282,317-331"
    note: "X68000 character generator ROM, read when neither X68030 font is present."
@@ -131,7 +130,6 @@ files:
    path: "cgrom.tmp"
    group: font
    priority: 4
-    required: true
    unsourceable: "rendered from TrueType fonts by the font generator, no canonical file"
    size: 786432
    source_ref: "SDL/SDL2/winx68k.cpp:280-282,317-331, SDL/tool/create_cgrom.c:20"
@@ -40,6 +40,12 @@ systems:
 #   <system_dir>/keropi/sram.dat       (auto-created)
 #   <system_dir>/keropi/config         (auto-created, core settings)

+groups:
+  ipl:
+    required: true
+  font:
+    required: true
+
 files:
  # IPL ROM, the main system BIOS. The core tries four filenames in order and
  # uses the first one found. Only one is needed. iplrom.dat is the original X68000,
@@ -51,7 +57,6 @@ files:
    group: ipl
    priority: 1
    size: 131072
-    required: true
    note: >
      X68000 IPL ROM (original model). 128 KB, loaded at IPL buffer offset 0x20000.
      The core tries iplrom.dat first, then iplrom30.dat, iplromco.dat, iplromxv.dat
@@ -63,7 +68,6 @@ files:
    group: ipl
    priority: 2
    size: 131072
-    required: true
    note: >
      X68030 IPL ROM. Alternative to iplrom.dat for X68030 model emulation.
      Only used if iplrom.dat is not found.
@@ -74,7 +78,6 @@ files:
    group: ipl
    priority: 3
    size: 131072
-    required: true
    note: >
      X68000 Compact IPL ROM. Alternative to iplrom.dat.
      Only used if iplrom.dat and iplrom30.dat are not found.
@@ -85,7 +88,6 @@ files:
    group: ipl
    priority: 4
    size: 131072
-    required: true
    note: >
      X68000 XVI IPL ROM. Last fallback in the IPL search order.
      Only used if the three other IPL variants are not found.
@@ -99,7 +101,6 @@ files:
    size: 786432
    group: font
    priority: 1
-    required: true
    note: >
      X68000 character generator ROM. 768 KB, provides the font glyphs for text
      display. If missing, the core falls back to cgrom.tmp (user-generated font
@@ -111,7 +112,6 @@ files:
    size: 786432
    group: font
    priority: 2
-    required: true
    unsourceable: "generated by WinX68k from the host fonts, no canonical file"
    note: >
      Alternative font file, used as fallback when cgrom.dat is absent.
@@ -104,7 +104,7 @@ files:
    system: flash
    required: true
    bundled: true
-    variant_group: "ruffle-core"
+    selection_slot: "ruffle-core"
    size: 90386
    md5: 5b1d64812875a1341ebd2a611e9324a1
    sha1: 0eabbed786f3b8e5656d123e9f4573f918ba63d8
@@ -119,7 +119,7 @@ files:
    system: flash
    required: true
    bundled: true
-    variant_group: "ruffle-core"
+    selection_slot: "ruffle-core"
    size: 13107470
    md5: 834f85979115fd740943a782887d0ab0
    sha1: d27da38e4d37727a44bf04d7690a09135fad7115
@@ -134,7 +134,7 @@ files:
    system: flash
    required: true
    bundled: true
-    variant_group: "ruffle-core"
+    selection_slot: "ruffle-core"
    size: 94169
    md5: 5aee868a91c066cc15f8b06999af690b
    sha1: 45815723a1bdf4229e289906bf4e52dbfd78da56
@@ -149,7 +149,7 @@ files:
    system: flash
    required: true
    bundled: true
-    variant_group: "ruffle-core"
+    selection_slot: "ruffle-core"
    size: 13323601
    md5: fe843bd0152c714f0449493b0193108f
    sha1: fea8e60e86cba7a63258626b13e6adb69ed110f9
@@ -58,11 +58,14 @@ notes: |
  or MPEG ROM path is passed, so no other firmware is read.
  ref: yabause/src/libretro/libretro.c:1078-1087, yabause/src/libretro/libretro.c:1898-1902

+groups:
+  saturn-bios:
+    required: true
+
 files:
  - name: "saturn_bios.bin"
    system: sega-saturn
    group: saturn-bios
-    required: true
    max_size: 524288
    validation: [max_size]
    note: "Any region. Second choice for every disc region."
@@ -71,7 +74,6 @@ files:
  - name: "sega_101.bin"
    system: sega-saturn
    group: saturn-bios
-    required: true
    region: [japan, asia-ntsc, south-korea]
    max_size: 524288
    validation: [max_size]
@@ -81,7 +83,6 @@ files:
  - name: "mpr-17933.bin"
    system: sega-saturn
    group: saturn-bios
-    required: true
    region: [north-america, europe, oceania, asia-pal, brazil, latin-america]
    max_size: 524288
    validation: [max_size]
@@ -80,13 +80,16 @@ notes: |
  Both build the pi4-update tip and patch the home directory to
  /storage/.config/yabasanshiro.

+groups:
+  saturn-bios:
+    required: true
+
 files:
  - name: "saturn_bios.bin"
    system: sega-saturn
    mode: libretro
    group: saturn-bios
    priority: 1
-    required: true
    note: "Primary Saturn BIOS. Any region accepted."
    source_ref: "yabause/src/libretro/libretro.c:1048"

@@ -95,7 +98,6 @@ files:
    mode: libretro
    group: saturn-bios
    priority: 2
-    required: true
    note: "Saturn BIOS v1.01 (Japan). Fallback if saturn_bios.bin missing."
    source_ref: "yabause/src/libretro/libretro.c:1052"

@@ -104,6 +106,5 @@ files:
    mode: libretro
    group: saturn-bios
    priority: 3
-    required: true
    note: "Saturn BIOS v1.003 (NA/EU). Last fallback."
    source_ref: "yabause/src/libretro/libretro.c:1056"
@@ -47,12 +47,15 @@ notes: |
  BIOS loading: retro_load_game() at yabause/src/libretro/libretro.c:1035-1049.
  Core load: LoadBios() at yabause/src/memory.c:1260-1263, T123Load() at yabause/src/memory.h:196-265.

+groups:
+  saturn-bios:
+    required: true
+
 files:
  - name: "saturn_bios.bin"
    system: sega-saturn
    group: saturn-bios
    priority: 1
-    required: true
    hle_fallback: true
    max_size: 524288
    validation: [max_size]
@@ -63,7 +66,6 @@ files:
    system: sega-saturn
    group: saturn-bios
    priority: 2
-    required: true
    hle_fallback: true
    max_size: 524288
    validation: [max_size]
@@ -74,7 +76,6 @@ files:
    system: sega-saturn
    group: saturn-bios
    priority: 3
-    required: true
    hle_fallback: true
    max_size: 524288
    validation: [max_size]
@@ -78,6 +78,10 @@ notes: |
  XXH128 hashes used for ROM identification only, not validation.
  All file loading validates size only.

+groups:
+  ipl:
+    required: true
+
 files:
  - name: "sega_101.bin"
    system: sega-saturn
@@ -98,7 +102,6 @@ files:
    region: [japan]
    group: ipl
    priority: 1
-    required: true
    mode: libretro
    size: 524288
    validation: [size]
@@ -113,7 +116,6 @@ files:
    region: [north-america, europe, asia-ntsc, asia-pal, brazil, latin-america]
    group: ipl
    priority: 2
-    required: true
    mode: libretro
    size: 524288
    validation: [size]
@@ -127,7 +129,6 @@ files:
    system: sega-saturn
    group: ipl
    priority: 3
-    required: true
    mode: libretro
    size: 524288
    validation: [size]
@@ -1158,7 +1158,6 @@ files:
    required: false
    bundled: true
    system: jupiter-ace
-    variant_group: "jupiter-ace-rom"
    source_ref: "src/ALTERNATEROMS:11-12, src/start.c:4877-4881"
    note: "Jupiter Ace ROM patched by Dutra Lacerda, distinct from the root ace.rom."

@@ -497,6 +497,19 @@
        "type": "string"
      }
    },
+    "groups": {
+      "description": "The sets of entries the code takes one of, by name, with the requirement of each. A member names its sets with group and writes no required of its own: it is required when one of its sets is.",
+      "type": "object",
+      "minProperties": 1,
+      "additionalProperties": {
+        "type": "object",
+        "additionalProperties": false,
+        "required": ["required"],
+        "properties": {
+          "required": {"type": "boolean"}
+        }
+      }
+    },
    "files": {
      "type": "array",
      "items": {
@@ -679,10 +692,11 @@
            "minimum": 0
          },
          "group": {
-            "description": "Entries of one profile sharing a group are one need: the code loads one of them (the first it finds, in priority order where the source states one) and holding any member fills it. required states the set's requirement and is the same on every member. A list puts a file in several sets, a fallback two machine models share.",
+            "description": "The sets of the profile's groups map this entry belongs to. A set is one need: the code loads one member (the first it finds, in priority order where the source states one) and holding any member fills it. A list puts a file in several sets, a fallback two machine models share, and a map from set to rank gives its place in each when the places differ (priority otherwise). The entry writes no required: it is derived from its sets.",
            "oneOf": [
              {"type": "string", "minLength": 1},
-              {"type": "array", "minItems": 1, "uniqueItems": true, "items": {"type": "string", "minLength": 1}}
+              {"type": "array", "minItems": 1, "uniqueItems": true, "items": {"type": "string", "minLength": 1}},
+              {"type": "object", "minProperties": 1, "additionalProperties": {"type": ["integer", "null"], "minimum": 0}}
            ]
          },
          "region_check": {
@@ -701,7 +715,8 @@
              "directory"
            ]
          },
-          "variant_group": {
+          "selection_slot": {
+            "description": "Files one core chooses between by a rule other than first found: the disc's territory, a core option, a feature probe. They fill one slot of the core whatever system each is filed under, region filtering compares them together, and same-named entries in different slots stay apart. A member does not stand in for another: entries that do are a group.",
            "type": "string",
            "minLength": 1
          },
@@ -941,6 +956,9 @@
              ]
            }
          },
+          {
+            "not": {"required": ["group", "required"]}
+          },
          {
            "if": {
              "properties": {
@@ -3,32 +3,88 @@
 A profile writes ``group:`` on the entries of one search list. Yabause tries
 saturn_bios.bin, sega_101.bin, then mpr-17933.bin and loads the first it
 finds (libretro.c:1035-1049): it needs one of them and none in particular.
-``required`` on a member states the set's requirement, and ``priority`` keeps
-the order the code reads them in.
+The requirement belongs to the set, in the profile's ``groups:`` map, and a
+member's ``required`` is derived from the sets it is in: true when one of
+them is required. A fallback two machine models share (pom2's apple2.rom)
+then needs no value of its own. ``priority`` keeps the order the code reads
+the members in.

 Holding one member fills the set, so the other members are not missing. A
-set nobody holds is one gap, reported under its first member, never one gap
-per member. Every reader settles sets through ``settle_sets`` so that verify,
-the gap report and the packs agree on what is missing.
+set nobody holds is one gap, reported under its first member with the set's
+requirement, never one gap per member. A --required-only build keeps one
+member of a required set, the first the code would load among those held.
+Every reader goes through this module so that verify, the gap report, the
+packs and the manifests agree.
 """

 from __future__ import annotations

-from collections.abc import Hashable, Iterable, Sequence
+from collections.abc import Callable, Hashable, Iterable, Sequence
+from dataclasses import dataclass

 _UNRANKED = 1 << 30


 def groups_of(entry: dict) -> tuple[str, ...]:
-    """The sets an entry belongs to: one name, or a list for a file two
-    machine models both fall back on."""
+    """The sets an entry belongs to: one name, a list for a file two machine
+    models both fall back on, or a map from set to the entry's rank there."""
    value = entry.get("group")
    if not value:
        return ()
-    values = value if isinstance(value, list) else [value]
+    values = value if isinstance(value, (list, dict)) else [value]
    return tuple(str(v) for v in values if v)


+def rank_in(entry: dict, group: str) -> int | None:
+    """The rank of an entry in one of its sets: the map's value when the
+    entry ranks differently in each (pom2's apple2.rom is second for the ][
+    and third at boot), else its priority."""
+    value = entry.get("group")
+    if isinstance(value, dict) and isinstance(value.get(group), int):
+        return value[group]
+    priority = entry.get("priority")
+    return priority if isinstance(priority, int) else None
+
+
+def set_requirements(profile: dict) -> dict[str, bool]:
+    """The requirement of each set the profile declares."""
+    declared = profile.get("groups") or {}
+    return {
+        str(name): bool((spec or {}).get("required", True))
+        for name, spec in declared.items()
+    }
+
+
+def derive_member_requirements(profile: dict) -> None:
+    """Write on each member the requirement its sets give it.
+
+    Read once when a profile is loaded, so every reader sees ``required``
+    as it always has. A member is required when one of its sets is.
+    """
+    requirements = set_requirements(profile)
+    for entry in profile.get("files") or []:
+        if not isinstance(entry, dict):
+            continue
+        names = groups_of(entry)
+        if names and "required" not in entry:
+            entry["required"] = any(requirements.get(n, True) for n in names)
+
+
+def required_groups(entry: dict, profile: dict) -> list[str]:
+    """The required sets of its profile an entry is a member of."""
+    requirements = set_requirements(profile)
+    return [n for n in groups_of(entry) if requirements.get(n, True)]
+
+
+def set_fields(entry: dict, profile: dict) -> dict:
+    """What a --required-only build reads on a core file to keep one member
+    of a set: the entry's required sets, each with its rank there."""
+    sets = required_groups(entry, profile)
+    if not sets:
+        return {}
+    return {"required_groups": {group: rank_in(entry, group) for group in sets}}
+
+
 def set_keys(owner: Hashable, entry: dict) -> tuple[tuple, ...]:
    """The keys of an entry's sets, scoped to its owner (a profile, or a
    profile under one build)."""
@@ -45,39 +101,48 @@ def slot_set_keys(owner: Hashable, entries: Iterable[dict]) -> tuple[tuple, ...]
    return tuple(keys)


-def _rank(entry: dict, position: int) -> tuple[int, int]:
-    priority = entry.get("priority")
-    return (priority if isinstance(priority, int) else _UNRANKED, position)
+def _rank(rank: int | None, position: int) -> tuple[int, int]:
+    return (rank if isinstance(rank, int) else _UNRANKED, position)
+
+
+@dataclass
+class Standing:
+    """The member kept as the one gap of the sets nobody holds."""
+
+    others: list[str]
+    required: bool


 def settle_sets(
    members: Sequence[tuple[tuple[tuple, ...], dict, bool]],
-) -> tuple[set[int], dict[int, list[str]]]:
+    set_required: Callable[[tuple], bool] = lambda _key: True,
+) -> tuple[set[int], dict[int, Standing]]:
    """Which unheld members are excused, and which one stands for its set.

    ``members`` lists ``(set keys, entry, fills)`` in the order the profile
    declares them, where ``fills`` says the member is held (or answered by a
    declaration that reports it). Returns the positions to leave out of a
    report and, for each set no member fills, the position kept as its one
-    gap with the names of the others. A member fills or not on its own: a
-    held one is never excused, and an unheld one stays reported when it
-    stands for at least one unfilled set.
+    gap with the names of the others and the set's requirement. A member
+    fills or not on its own: a held one is never excused, and an unheld one
+    stays reported when it stands for at least one unfilled set.
    """
    by_set: dict[tuple, list[int]] = {}
    for position, (keys, _entry, _fills) in enumerate(members):
        for key in keys:
            by_set.setdefault(key, []).append(position)

-    standing: dict[int, list[str]] = {}
-    for positions in by_set.values():
+    standing: dict[int, Standing] = {}
+    for key, positions in by_set.items():
        if any(members[p][2] for p in positions):
            continue
-        first = min(positions, key=lambda p: _rank(members[p][1], p))
-        names = standing.setdefault(first, [])
+        first = min(positions, key=lambda p: _rank(rank_in(members[p][1], key[1]), p))
+        held_up = standing.setdefault(first, Standing([], False))
+        held_up.required = held_up.required or set_required(key)
        for p in positions:
            name = str(members[p][1].get("name", ""))
-            if p != first and name not in names:
-                names.append(name)
+            if p != first and name not in held_up.others:
+                held_up.others.append(name)

    excused = {
        position
@@ -85,3 +150,58 @@ def settle_sets(
        if keys and not fills and position not in standing
    }
    return excused, standing
+
+
+def required_only_spares(
+    entries: Sequence[dict],
+    owner: Callable[[dict], Hashable],
+    held: Callable[[dict], bool],
+    gone: Callable[[dict], bool] = lambda _entry: False,
+    sets: Callable[[dict], dict[str, int | None]] = lambda e: e.get("required_groups") or {},
+) -> set[int]:
+    """The ids of the held members a --required-only build leaves out.
+
+    ``sets`` maps the required sets of an entry to its rank in each: a core
+    file of a platform pack carries them as ``required_groups``.
+
+    A required set needs one file: the build keeps the member the code
+    would load first among those it holds and still carries (``gone`` says
+    a region filter took it), by ``priority`` then declaration order, and
+    drops the others. A member of an optional set is not touched here,
+    nor one that another required set of its own still needs.
+    """
+    candidates: dict[tuple, list[tuple[tuple[int, int], int]]] = {}
+    for position, entry in enumerate(entries):
+        if not held(entry) or gone(entry):
+            continue
+        for group, rank in sets(entry).items():
+            candidates.setdefault((owner(entry), group), []).append(
+                (_rank(rank, position), position)
+            )
+    kept: set[int] = set()
+    members: set[int] = set()
+    for ranked in candidates.values():
+        members.update(position for _rank_key, position in ranked)
+        kept.add(min(ranked)[1])
+    return {id(entries[p]) for p in members - kept}
+
+
+def core_file_spares(
+    entries: Sequence[dict], gone: Callable[[dict], bool] = lambda _entry: False,
+) -> set[int]:
+    """The core files of a platform pack a --required-only build leaves out.
+
+    A set the platform declares a member of is carried by that declaration,
+    so its other members are spares. Otherwise one held member per required
+    set stays, as in an emulator pack. Read by the builder, the manifest
+    and verify alike.
+    """
+    answered = {id(e) for e in entries if e.get("set_declared")}
+    rest = [e for e in entries if id(e) not in answered]
+    return answered | required_only_spares(
+        rest,
+        owner=lambda e: e.get("source_profile") or e.get("profile") or "",
+        held=lambda e: e.get("in_repo", True) is not False,
+        gone=gone,
+    )
+
@@ -22,6 +22,8 @@ import zipfile
 from pathlib import Path
 from typing import Any, TextIO

+from alternatives import derive_member_requirements
+
 # Every build script imports this module. verify.py, slots.py, validate_pr.py
 # and cross_reference.py started under 3.8 and stopped halfway on a
 # str.removeprefix AttributeError, which named no version.
@@ -2346,6 +2348,7 @@ def load_emulator_profiles(
        if "emulator" not in profile:
            continue
        _normalize_hash_fields(profile)
+        derive_member_requirements(profile)
        profiles[f.stem] = profile
    _emulator_profiles_cache[cache_key] = profiles
    return profiles
@@ -23,7 +23,7 @@ from collections import Counter
 from pathlib import Path

 sys.path.insert(0, os.path.dirname(__file__))
-from alternatives import set_keys, settle_sets
+from alternatives import set_keys, set_requirements, settle_sets
 from common import (
    platform_arg,
    ProfileSelectionError,
@@ -697,7 +697,7 @@ def slot_key(f: dict, standalone: bool = False) -> tuple:
        f.get("archive"),
        system_dir_path(f, where or fname),
        f.get("system"),
-        f.get("variant_group"),
+        f.get("selection_slot"),
        f.get("mode", "both"),
        read_from_save_dir(f, standalone),
    )
@@ -886,7 +886,7 @@ def _cross_reference_profile(
            archive_key = (
                archive,
                f.get("system"),
-                f.get("variant_group"),
+                f.get("selection_slot"),
                f.get("mode", "both"),
            )
            if archive_key not in archive_gaps:
@@ -969,12 +969,17 @@ def _cross_reference_profile(
    # nobody holds is one gap under its first member (alternatives.py), as
    # verify and the packs count it.
    grouped = [r for r in set_records if r[0]]
-    excused, standing = settle_sets([(keys, f, fills) for keys, f, fills, _l, _r in grouped])
+    requirements = set_requirements(profile)
+    excused, standing = settle_sets(
+        [(keys, f, fills) for keys, f, fills, _l, _r in grouped],
+        lambda key: requirements.get(key[1], True),
+    )
    for at, (_keys, member, _fills, rows, set_row) in enumerate(grouped):
        if set_row is None or rows is None:
            continue
        if at in standing:
-            set_row["alternatives"] = standing[at]
+            set_row["alternatives"] = standing[at].others
+            set_row["required"] = standing[at].required
        if at in excused:
            rows.remove(set_row)
            fates[position[id(member)]] = "other_versions"
@@ -36,7 +36,7 @@ import zipfile
 from pathlib import Path, PurePosixPath

 sys.path.insert(0, os.path.dirname(__file__))
-from alternatives import settle_sets, slot_set_keys
+from alternatives import core_file_spares, settle_sets, slot_set_keys
 from common import resolve_platform_cores as _platform_cores
 from common import (
    installed_data_refs,
@@ -1295,8 +1295,13 @@ def generate_pack(
          db, bios_dir, zip_contents, data_registry, validation_index,
          validation_owners, offline, profiles=emu_profiles,
      )
+      spares = core_file_spares(
+          core_files,
+          lambda fe: bool(region_drops)
+          and extra_region_key(fe, declared_root(config)) in region_drops,
+      ) if required_only else set()
      for fe in core_files:
-          if required_only and fe.get("required") is False:
+          if required_only and (fe.get("required") is False or id(fe) in spares):
              continue
          dest = sanitize_pack_path(fe.get("destination", fe["name"]))
          if region_drops and extra_region_key(fe, declared_root(config)) in region_drops:
@@ -1434,8 +1439,13 @@ def generate_pack(
          if system_filter:
              unfolded = _extras_for_systems(unfolded, system_filter)
          prefix = _detect_extras_prefix(config, base_dest)
+          unfolded_spares = core_file_spares(
+              unfolded,
+              lambda fe: bool(region_drops)
+              and extra_region_key(fe, declared_root(config)) in region_drops,
+          ) if required_only else set()
          for fe in unfolded:
-              if required_only and fe.get("required") is False:
+              if required_only and (fe.get("required") is False or id(fe) in unfolded_spares):
                  continue
              if region_drops and extra_region_key(fe, declared_root(config)) in region_drops:
                  continue
@@ -1826,9 +1836,13 @@ def generate_emulator_pack(
            # there (raze's seven SW.GRP): the first one the core accepts
            # fills the slot, as verify --emulator credits it, and the slot
            # has one outcome however many alternatives it lists.
+            spares = emulator_required_spares(
+                emu_name, profile, files, standalone, region_drops, db,
+                validation_index, zip_contents, data_registry,
+            ) if required_only else set()
            slots: dict[str, list[dict]] = {}
            for fe in files:
-                if required_only and fe.get("required") is False:
+                if required_only and (fe.get("required") is False or id(fe) in spares):
                    continue
                if fe.get("archive"):
                    continue
@@ -4398,8 +4412,13 @@ def _manifest_core_entries(
        db, bios_dir, zip_contents, data_registry, validation_index or {},
        owners, offline, profiles=profiles,
    )
+    spares = core_file_spares(
+        core_files,
+        lambda fe: bool(region_drops)
+        and extra_region_key(fe, declared_root(config)) in region_drops,
+    ) if required_only else set()
    for fe in core_files:
-        if required_only and fe.get("required") is False:
+        if required_only and (fe.get("required") is False or id(fe) in spares):
            continue
        dest = sanitize_pack_path(fe.get("destination", fe["name"]))
        if not dest:
@@ -5770,6 +5789,7 @@ from packextras import (  # noqa: E402,F401
    extras_for_systems as _extras_for_systems,
    platform_region_groups,
    emulator_region_drops,
+    emulator_required_spares,
    _emulator_region_group,
    expand_agnostic_entries,
    undeclared_report,
@@ -1115,7 +1115,7 @@ def _platform_export_rows(
                    ),
                    "required": bool(entry.get("required", True)),
                    "region": _json_text(entry.get("region")),
-                    "variant_group": _json_text(entry.get("variant_group")),
+                    "selection_slot": _json_text(entry.get("selection_slot")),
                    "size": entry.get("size"),
                    "sha1": _json_text(entry.get("sha1")),
                    "sha256": _json_text(entry.get("sha256")),
@@ -1371,7 +1371,7 @@ def _write_sqlite_export(
            CREATE TABLE platform_files (
                platform_id TEXT NOT NULL, system TEXT NOT NULL, name TEXT NOT NULL,
                destination TEXT NOT NULL, required INTEGER NOT NULL,
-                region TEXT, variant_group TEXT, size INTEGER,
+                region TEXT, selection_slot TEXT, size INTEGER,
                sha1 TEXT, sha256 TEXT, md5 TEXT, crc32 TEXT,
                status TEXT, category TEXT, collection_path TEXT, resolved_sha1 TEXT,
                zipped_file TEXT, hash_match_mandatory INTEGER, mandatory_declared INTEGER,
@@ -1454,7 +1454,7 @@ def _write_sqlite_export(
        connection.executemany(
            "INSERT INTO platform_files VALUES "
            "(:platform_id, :system, :name, :destination, :required, :region, "
-            ":variant_group, :size, :sha1, :sha256, :md5, :crc32, :status, :category, "
+            ":selection_slot, :size, :sha1, :sha256, :md5, :crc32, :status, :category, "
            ":collection_path, :resolved_sha1, :zipped_file, :hash_match_mandatory, "
            ":mandatory_declared, :curated, :shared_group, :mirror_of, :zip_digest)",
            platform_files,
@@ -1698,7 +1698,7 @@ def generate_data_exports(
        _csv_document(
            [
                "platform_id", "platform", "system", "name", "destination",
-                "required", "region", "variant_group", "size", "sha1",
+                "required", "region", "selection_slot", "size", "sha1",
                "sha256", "md5", "crc32", "status", "category",
                "collection_path", "resolved_sha1", *ENTRY_EXPORT_FIELDS,
            ],
@@ -643,7 +643,7 @@ def _launcher_entry(
    entry = {
        key: report.get(key)
        for key in (
-            "profile", "emulator", "systems", "system", "region", "variant_group",
+            "profile", "emulator", "systems", "system", "region", "selection_slot",
            "required", "hle_fallback", "category",
        )
    }
@@ -9,6 +9,7 @@ from __future__ import annotations
 from collections.abc import Iterable

 from common import PROFILE_IDENTITY_FIELDS, _norm_system_id, entry_system_ids
+from alternatives import core_file_spares, required_only_spares, set_fields
 from common import archive_members, holds_required_members
 from common import declared_root, expand_platform_declared_names, platform_declarations
 from common import load_emulator_profiles
@@ -388,8 +389,12 @@ def hidden_extras(
    )
    if system_ids:
        extras = extras_for_systems(extras, system_ids)
+    spares = core_file_spares(
+        extras,
+        lambda fe: extra_region_key(fe, region_prefix) in (region_drops or set()),
+    ) if required_only else set()
    for fe in extras:
-        if required_only and fe.get("required") is False:
+        if required_only and (fe.get("required") is False or id(fe) in spares):
            continue
        dest = sanitize_pack_path(fe.get("destination", fe.get("name", "")))
        if not dest or (region_drops and extra_region_key(fe, region_prefix) in region_drops):
@@ -640,7 +645,7 @@ def _agnostic_scan_extras(
                        "source_system": f.get("system"),
                        "source_systems": entry_system_ids(f, profile),
                        "region": f.get("region"),
-                        "variant_group": f.get("variant_group"),
+                        "selection_slot": f.get("selection_slot"),
                        "agnostic_scan": True,
                    }
                    extra["claim_order"] = (4, 0, emu_name)
@@ -796,7 +801,7 @@ def _companion_extras(
            "source_system": seed.get("system"),
            "source_systems": entry_system_ids(seed, profile),
            "region": seed.get("region"),
-            "variant_group": seed.get("variant_group"),
+            "selection_slot": seed.get("selection_slot"),
            "agnostic_scan": True,
        }
        extra["claim_order"] = (4, 0, emu_name)
@@ -970,7 +975,7 @@ def _archive_prefix_copies(
            "source_system": archive_entry.get("system"),
            "source_systems": entry_system_ids(archive_entry, profile),
            "region": archive_entry.get("region"),
-            "variant_group": archive_entry.get("variant_group"),
+            "selection_slot": archive_entry.get("selection_slot"),
        }
        members = archive_members(archive_name, profile.get("files", []))
        if members:
@@ -1354,7 +1359,8 @@ def _collect_emulator_extras(
                    "source_system": f.get("system"),
                    "source_systems": entry_system_ids(f, profile),
                    "region": f.get("region"),
-                    "variant_group": f.get("variant_group"),
+                    "selection_slot": f.get("selection_slot"),
+                    **set_fields(f, profile),
                }
                # The same identity the first pass carries: without it the copy
                # resolves on its name alone and a same-named file of another
@@ -1522,7 +1528,8 @@ def _report_extra(u: dict, name: str, dest: str) -> dict:
        "source_system": u.get("system"),
        "source_systems": u.get("systems", []),
        "region": u.get("region"),
-        "variant_group": u.get("variant_group"),
+        "selection_slot": u.get("selection_slot"),
+        **{k: u[k] for k in ("required_groups", "set_declared") if k in u},
    }
    if u.get("members"):
        extra["members"] = u["members"]
@@ -1795,9 +1802,9 @@ def extra_region_groups(
        return (spellings or {}).get(_norm_system_id(sys_id), sys_id)

    emulator = extra.get("source_emulator", "")
-    variant = extra.get("variant_group")
+    variant = extra.get("selection_slot")
    if variant:
-        # A variant group is one slot of one core, whatever system each
+        # A selection slot is one slot of one core, whatever system each
        # member is filed under: PicoDrive files its US Mega CD BIOS under
        # sega-segacd and the EU/JP ones under sega-megacd, and find_bios
        # picks one of the twelve. Keyed as emulator mode keys it.
@@ -1826,7 +1833,7 @@ def emulator_region_drops(
 ) -> set[str]:
    """Destinations an emulator-mode `--region` withdraws.

-    One group per system (or explicit variant_group) inside each profile, so
+    One group per system (or explicit selection_slot) inside each profile, so
    a multi-system core such as O2EM keeps a fallback BIOS for every system
    instead of letting one matching system empty another. The emulator pack
    and `verify --emulator` both read this, keyed by pack destination.
@@ -1864,6 +1871,38 @@ def emulator_region_drops(
    return region_mod.resolve_region_drops(region_groups, region_index, regions, held)


+def emulator_required_spares(
+    emu_name: str,
+    profile: dict,
+    files: list[dict],
+    standalone: bool,
+    region_drops: set[str],
+    db: dict,
+    validation_index: dict,
+    zip_contents: dict | None,
+    data_registry: dict | None,
+) -> set[int]:
+    """The members of required sets an emulator --required-only pack leaves
+    out: one held member stays per set, the first the code loads among those
+    the pack still carries after the region filter. The pack and
+    verify --emulator both read this."""
+    from alternatives import groups_of, rank_in, required_groups
+    from packpaths import _resolve_destination
+
+    loose = [fe for fe in files if not fe.get("archive") and groups_of(fe)]
+    if not loose:
+        return set()
+    return required_only_spares(
+        loose,
+        owner=lambda _fe: emu_name,
+        held=lambda fe: _emulator_ships(
+            fe, emu_name, profile, db, validation_index, zip_contents, data_registry,
+        ),
+        gone=lambda fe: _resolve_destination(fe, standalone) in region_drops,
+        sets=lambda fe: {g: rank_in(fe, g) for g in required_groups(fe, profile)},
+    )
+
+
 def _emulator_ships(
    file_entry: dict, emu_name: str, profile: dict, db: dict,
    validation_index: dict, zip_contents: dict | None, data_registry: dict | None,
@@ -1904,7 +1943,7 @@ def _emulator_region_group(
    Grouped together, geargrafx's LaserActive pac-n1.bin was dropped by
    --emulator --region us and kept by --platform --region us.
    """
-    variant = file_entry.get("variant_group")
+    variant = file_entry.get("selection_slot")
    if variant:
        return f"{emu_name}:variant:{variant}"
    system = file_entry.get("system")
@@ -127,7 +127,7 @@ def resolve_slot_drops(
    # A slot is a system AND a declared region: the Japanese and American
    # PlayStation BIOS are not alternatives to each other, and comparing their
    # ranks across regions would pick one territory's file for another's.
-    tiers: dict[tuple[str, tuple[str, ...], tuple], list[tuple[str, int | None]]] = {}
+    bucketed: dict[tuple[str, tuple[str, ...]], list[tuple[str, int | None, frozenset]]] = {}
    for group_id, members in groups.items():
        for destination, name in members:
            if held is not None and destination not in held:
@@ -136,14 +136,20 @@ def resolve_slot_drops(
            if entry is None:
                keep.add(destination)
                continue
-            # A rank orders the members of one set: px68k-sdl ranks its IPL
-            # and its font ROM lists each from 1, and the two never compete.
            tier = tuple(sorted(entry["regions"]))
-            sets = tuple(sorted(entry.get("sets") or ()))
            rank = None if entry.get("conflict") else entry["rank"]
-            tiers.setdefault((group_id, tier, sets), []).append((destination, rank))
+            bucketed.setdefault((group_id, tier), []).append(
+                (destination, rank, frozenset(entry.get("sets") or ()))
+            )
+    # A rank orders the members of one set: px68k-sdl ranks its IPL and its
+    # font ROM lists each from 1, and the two never compete. Candidates are
+    # compared when they share a set, and those in no set among themselves.
+    tiers: dict[tuple[str, tuple[str, ...], int], list[tuple[str, int | None]]] = {}
+    for (group_id, tier), found in bucketed.items():
+        for part, component in enumerate(_by_shared_set(found)):
+            tiers[(group_id, tier, part)] = component

-    for (group_id, tier, _sets), candidates in tiers.items():
+    for (group_id, tier, _part), candidates in tiers.items():
        if len(candidates) < 2:
            keep.update(dest for dest, _p in candidates)
            continue
@@ -167,3 +173,28 @@ def resolve_slot_drops(
        drop.update(dest for dest, _p in candidates if dest != winners[0])

    return drop - keep, sorted(undecidable)
+
+
+def _by_shared_set(
+    found: list[tuple[str, int | None, frozenset]],
+) -> list[list[tuple[str, int | None]]]:
+    """The candidates of one tier split where no set links them."""
+    parent = list(range(len(found)))
+
+    def root(i: int) -> int:
+        while parent[i] != i:
+            parent[i] = parent[parent[i]]
+            i = parent[i]
+        return i
+
+    first_of: dict[object, int] = {}
+    for i, (_dest, _rank, sets) in enumerate(found):
+        for key in sets or {None}:
+            if key in first_of:
+                parent[root(i)] = root(first_of[key])
+            else:
+                first_of[key] = i
+    parts: dict[int, list[tuple[str, int | None]]] = {}
+    for i, (dest, rank, _sets) in enumerate(found):
+        parts.setdefault(root(i), []).append((dest, rank))
+    return list(parts.values())
@@ -124,27 +124,33 @@ def _systems_outside_profile(path: Path, document: object) -> list[str]:


 def _group_requirement_split(path: Path, document: object) -> list[str]:
-    """A group whose members disagree on required.
+    """A set named by a member and not declared, declared and never used,
+    or a member that writes a required of its own.

-    The members of a group are one need, so required states the set's and
-    reads the same on each. A true on the first name only wrote the search
-    order into required, and the other names read as optional files.
+    The requirement belongs to the set, in the profile's groups map, and a
+    member's is derived from it. A value on the member is a second source
+    that can contradict the first: a true on the first name only wrote the
+    search order into required, and the other names read as optional.
    """
    from alternatives import groups_of

    if not isinstance(document, dict):
        return []
-    seen: dict[str, set[bool]] = {}
-    for entry in document.get("files") or []:
+    label = path.relative_to(ROOT)
+    declared = set((document.get("groups") or {}).keys())
+    used: set[str] = set()
+    out: list[str] = []
+    for index, entry in enumerate(document.get("files") or []):
        if not isinstance(entry, dict):
            continue
-        for group in groups_of(entry):
-            seen.setdefault(group, set()).add(bool(entry.get("required", True)))
-    return [
-        f"{path.relative_to(ROOT)}: group {group} mixes required true and false"
-        for group, values in sorted(seen.items())
-        if len(values) > 1
-    ]
+        names = groups_of(entry)
+        used.update(names)
+        if names and "required" in entry:
+            out.append(f"{label}: files[{index}] ({entry.get('name')}) is in a group "
+                       "and writes required: the set's requirement is in groups")
+    out.extend(f"{label}: group {g} has no entry in groups" for g in sorted(used - declared))
+    out.extend(f"{label}: groups declares {g}, which no entry names" for g in sorted(declared - used))
+    return out


 def _checks_without_values(path: Path, document: object) -> list[str]:
@@ -37,7 +37,14 @@ import slots

 sys.path.insert(0, os.path.dirname(__file__))
 from hashing import parse_md5_list
-from alternatives import set_keys, settle_sets, slot_set_keys
+from alternatives import (
+    core_file_spares,
+    set_fields,
+    set_keys,
+    set_requirements,
+    settle_sets,
+    slot_set_keys,
+)
 from common import (
    _foreign_tree,
    _owner_tokens,
@@ -591,7 +598,7 @@ def find_undeclared_files(
                    f.get("archive"),
                    dest,
                    f.get("system"),
-                    f.get("variant_group"),
+                    f.get("selection_slot"),
                    region_key,
                    # Below the save directory each core is handed a folder
                    # of its own: two cores reading hiscore.dat there read
@@ -625,7 +632,7 @@ def find_undeclared_files(
                        archive,
                        f.get("system_dir"),
                        f.get("system"),
-                        f.get("variant_group"),
+                        f.get("selection_slot"),
                        region_key,
                        is_standalone,
                    )
@@ -640,7 +647,7 @@ def find_undeclared_files(
                            "systems": entry_system_ids(f, profile),
                            "system": f.get("system"),
                            "region": f.get("region"),
-                            "variant_group": f.get("variant_group"),
+                            "selection_slot": f.get("selection_slot"),
                            "name": archive,
                            "archive": archive,
                            "path": system_dir_path(f, archive),
@@ -738,7 +745,7 @@ def find_undeclared_files(
                    "systems": entry_system_ids(f, profile),
                    "system": f.get("system"),
                    "region": f.get("region"),
-                    "variant_group": f.get("variant_group"),
+                    "selection_slot": f.get("selection_slot"),
                    "name": fname,
                    "path": dest,
                    "required": f.get("required", False),
@@ -748,6 +755,7 @@ def find_undeclared_files(
                    "in_repo": in_repo,
                    "note": f.get("note", ""),
                    "checks": sorted(checks) if checks else [],
+                    **set_fields(f, profile),
                    "source_ref": f.get("source_ref"),
                    "expected": _build_expected(f, checks),
                    **_identity_of(f),
@@ -785,7 +793,7 @@ def find_undeclared_files(
        undeclared = [u for u in undeclared if id(u) not in settled]
        undeclared.extend(added)

-    undeclared = _settle_core_sets(undeclared, set_records, settled)
+    undeclared = _settle_core_sets(undeclared, set_records, settled, profiles)

    for entry in sorted(archive_entries.values(), key=lambda e: e["name"]):
        undeclared.append(entry)
@@ -797,6 +805,7 @@ def _settle_core_sets(
    undeclared: list[dict],
    records: list[tuple[tuple, dict, bool, tuple[dict, dict | None] | None]],
    launcher_settled: set[int],
+    profiles: dict[str, dict],
 ) -> list[dict]:
    """The core complement with each set of alternatives settled.

@@ -811,14 +820,23 @@ def _settle_core_sets(
    excused, standing = settle_sets([
        (keys, f, fills or (ref is not None and id(ref[0]) in launcher_settled))
        for keys, f, fills, ref in grouped
-    ])
+    ], lambda key: set_requirements(profiles.get(key[0][0], {})).get(key[1], True))
+    declared_sets = {
+        key for keys, _f, _fills, ref in grouped if ref is None for key in keys
+    }
    dropped: set[int] = set()
-    for position, (_keys, _f, _fills, ref) in enumerate(grouped):
+    for position, (keys, _f, _fills, ref) in enumerate(grouped):
        if ref is None:
            continue
        entry, host = ref
+        required_keys = [k for k in keys if k[1] in entry.get("required_groups", ())]
+        if required_keys and all(k in declared_sets for k in required_keys):
+            # The platform declares a member of each of its required sets:
+            # under --required-only that declaration carries them.
+            entry["set_declared"] = True
        if position in standing:
-            entry["alternatives"] = standing[position]
+            entry["alternatives"] = standing[position].others
+            entry["required"] = standing[position].required
        if position not in excused:
            continue
        if host is not None:
@@ -1548,6 +1566,10 @@ def verify_platform(
            )
            not in region_drops
        ]
+    if required_only:
+        # One member of a required set, as the builder keeps it.
+        spares = core_file_spares(undeclared)
+        undeclared = [u for u in undeclared if id(u) not in spares]
    _mark_unplaced(config, undeclared, profiles)
    from packextras import ExtraResolver

@@ -2343,6 +2365,14 @@ def verify_emulator(
                if fe.get("archive")
                or _resolve_destination(fe, standalone) not in region_drops
            ]
+        if required_only:
+            from packextras import emulator_required_spares
+
+            spares = emulator_required_spares(
+                emu_name, profile, files, standalone, region_drops, db,
+                validation_index, zip_contents, data_registry,
+            )
+            files = [fe for fe in files if id(fe) not in spares]

        # Check data directories (only notice if not cached)
        for dd in deliverable(
@@ -2645,13 +2675,14 @@ def verify_emulator(
                    and result.get("reason") == fallback_reason),
            )
            for _dest, result, _required, _hle, entries in placed_results
-        ])
+        ], lambda key: set_requirements(profile).get(key[1], True))
        for position, (dest, result, required, hle, _fe) in enumerate(placed_results):
            if position in excused and result["status"] == Status.MISSING:
                set_members.append(result)
                continue
            if position in standing:
-                result["alternatives"] = standing[position]
+                result["alternatives"] = standing[position].others
+                result["required"] = required = standing[position].required
            details.append(result)

            # Aggregate by destination (path if available, else name)
@@ -6790,7 +6790,7 @@ class OneOfASearchList(unittest.TestCase):
        self.addCleanup(os.chdir, previous)
        self.db = {"files": {}, "indexes": {"by_md5": {}, "by_name": {},
                                            "by_crc32": {}, "by_path_suffix": {}}}
-        for name in ("second.bin", "plain.bin"):
+        for name in ("second.bin", "third.bin", "plain.bin"):
            data = name.encode() * 8
            rel = f"bios/Test/Console/{name}"
            Path(rel).parent.mkdir(parents=True, exist_ok=True)
@@ -6804,11 +6804,12 @@ class OneOfASearchList(unittest.TestCase):

        def member(name: str, group: str, rank: int) -> dict:
            return {"name": name, "system": "console-a", "group": group,
-                    "priority": rank, "required": True}
+                    "priority": rank}

-        self.profile = {
+        raw = {
            "emulator": "Seq", "type": "libretro", "cores": ["seq"],
            "systems": ["console-a"],
+            "groups": {"first": {"required": True}, "none": {"required": True}},
            "files": [
                member("first.bin", "first", 1),
                member("second.bin", "first", 2),
@@ -6818,7 +6819,10 @@ class OneOfASearchList(unittest.TestCase):
                {"name": "plain.bin", "system": "console-a", "required": True},
            ],
        }
-        Path("emulators/seq.yml").write_text(yaml.safe_dump(self.profile))
+        Path("emulators/seq.yml").write_text(yaml.safe_dump(raw))
+        self.raw = raw
+        # What every reader sees: the profile as load_emulator_profiles gives it.
+        self.profile = load_emulator_profiles("emulators")["seq"]
        self.config = {
            "platform": "Seqs", "verification_mode": "existence",
            "base_destination": "system", "cores": ["seq"],
@@ -6832,11 +6836,11 @@ class OneOfASearchList(unittest.TestCase):
        result = self._verify()
        reported = {d["name"]: d["status"] for d in result["details"]}
        self.assertEqual(reported["second.bin"], "ok")
+        self.assertEqual(reported["third.bin"], "ok")
        self.assertNotIn("first.bin", reported)
-        self.assertNotIn("third.bin", reported)
        self.assertEqual(
            sorted(d["name"] for d in result["set_members"]),
-            ["first.bin", "none_b.bin", "third.bin"],
+            ["first.bin", "none_b.bin"],
        )

    def test_a_set_none_holds_is_one_gap(self):
@@ -6848,7 +6852,7 @@ class OneOfASearchList(unittest.TestCase):
        self.assertEqual(result["severity_counts"][Severity.WARNING], 1)
        self.assertEqual(result["severity_counts"][Severity.INFO], 0)
        self.assertEqual(result["status_counts"].get("missing"), 1)
-        self.assertEqual(result["total_files"], 3)
+        self.assertEqual(result["total_files"], 4)

    def test_a_required_set_held_through_a_later_member_is_satisfied(self):
        """second.bin used to read required: false beside a required
@@ -6876,21 +6880,23 @@ class OneOfASearchList(unittest.TestCase):
            )
        with zipfile.ZipFile(zip_path) as zf:
            packed = sorted(n for n in zf.namelist() if n != "README.txt")
-        self.assertEqual(packed, ["plain.bin", "second.bin"])
+        self.assertEqual(packed, ["plain.bin", "second.bin", "third.bin"])
        self.assertEqual(result["severity_counts"]["ok"], len(packed))
        lines = out.getvalue().splitlines()
        self.assertEqual(
            [line.split(": ", 1)[1] for line in lines if line.strip().startswith("MISSING:")],
            ["none_a.bin"],
        )
-        self.assertIn("2 files packed, 1 missing", out.getvalue())
+        self.assertIn("3 files packed, 1 missing", out.getvalue())

    def test_core_complement_reports_one_gap_per_set(self):
        undeclared = find_undeclared_files(
            self.config, "emulators", self.db, {"seq": self.profile}
        )
        by_name = {u["name"]: u for u in undeclared}
-        self.assertEqual(sorted(by_name), ["none_a.bin", "plain.bin", "second.bin"])
+        self.assertEqual(
+            sorted(by_name), ["none_a.bin", "plain.bin", "second.bin", "third.bin"]
+        )
        self.assertTrue(by_name["second.bin"]["in_repo"])
        self.assertFalse(by_name["none_a.bin"]["in_repo"])
        self.assertEqual(by_name["none_a.bin"]["alternatives"], ["none_b.bin"])
@@ -6905,7 +6911,9 @@ class OneOfASearchList(unittest.TestCase):
        undeclared = find_undeclared_files(
            config, "emulators", self.db, {"seq": self.profile}
        )
-        self.assertEqual(sorted(u["name"] for u in undeclared), ["plain.bin", "second.bin"])
+        self.assertEqual(
+            sorted(u["name"] for u in undeclared), ["plain.bin", "second.bin", "third.bin"]
+        )

    def test_gap_report_counts_the_set_once(self):
        import cross_reference
@@ -6919,14 +6927,14 @@ class OneOfASearchList(unittest.TestCase):
        report: dict = {}
        cross_reference._cross_reference_profile("seq", self.profile, {}, report, index)
        gaps = {g["name"]: g for g in report["seq"]["gap_details"]}
-        self.assertEqual(sorted(gaps), ["none_a.bin", "plain.bin", "second.bin"])
+        self.assertEqual(sorted(gaps), ["none_a.bin", "plain.bin", "second.bin", "third.bin"])
        self.assertEqual(gaps["none_a.bin"]["alternatives"], ["none_b.bin"])
-        self.assertEqual(report["seq"]["set_aside"]["other_versions"], 3)
+        self.assertEqual(report["seq"]["set_aside"]["other_versions"], 2)

    def test_truth_names_no_member_required_on_its_own(self):
        from truth import _fold_into, _new_truth_entry

-        entry = _new_truth_entry(self.profile["files"][0], "seq", None)
+        entry = _new_truth_entry(dict(self.profile["files"][0]), "seq", None)
        self.assertNotIn("required", entry)
        self.assertEqual(entry["_required_by"], set())
        self.assertTrue(entry["one_of_required"])
@@ -6974,10 +6982,56 @@ class OneOfASearchList(unittest.TestCase):
        from validate_schemas import _group_requirement_split, ROOT

        path = ROOT / "emulators" / "seq.yml"
-        split = {"files": [{"name": "a", "group": "g", "required": True},
-                           {"name": "b", "group": "g", "required": False}]}
-        self.assertEqual(len(_group_requirement_split(path, split)), 1)
-        self.assertEqual(_group_requirement_split(path, {"files": self.profile["files"]}), [])
+        own_value = {"groups": {"g": {"required": True}},
+                     "files": [{"name": "a", "group": "g", "required": False},
+                               {"name": "b", "group": "g"}]}
+        self.assertEqual(len(_group_requirement_split(path, own_value)), 1)
+        undeclared_set = {"files": [{"name": "a", "group": "g"}]}
+        self.assertEqual(len(_group_requirement_split(path, undeclared_set)), 1)
+        unused = {"groups": {"g": {"required": True}}, "files": [{"name": "a"}]}
+        self.assertEqual(len(_group_requirement_split(path, unused)), 1)
+        self.assertEqual(_group_requirement_split(path, self.raw), [])
+
+    def test_a_shared_fallback_takes_its_requirement_from_its_sets(self):
+        """pom2 falls back on apple2e.rom for the //e it boots by default
+        and for the unenhanced //e it may be switched to. One value on the
+        file cannot say both: the sets carry it."""
+        from alternatives import derive_member_requirements
+
+        profile = {"groups": {"iie": {"required": True}, "iie-u": {"required": False}},
+                   "files": [{"name": "apple2e_unenh.rom", "group": "iie-u"},
+                             {"name": "apple2e.rom", "group": ["iie", "iie-u"]}]}
+        derive_member_requirements(profile)
+        self.assertEqual([f["required"] for f in profile["files"]], [False, True])
+
+    def test_required_only_keeps_one_held_member_per_required_set(self):
+        """second.bin and third.bin are both held: a --required-only pack
+        carries second.bin, the first the code reads among those held, and
+        verify reports the same single file."""
+        from generate_pack import generate_emulator_pack
+
+        result = verify_emulator(["seq"], "emulators", self.db,
+                                 platforms_dir="platforms", required_only=True)
+        held = sorted(d["name"] for d in result["details"] if d["status"] == "ok")
+        self.assertEqual(held, ["plain.bin", "second.bin"])
+        with contextlib.redirect_stdout(io.StringIO()):
+            zip_path = generate_emulator_pack(
+                ["seq"], "emulators", self.db, "bios", "out", offline=True,
+                platforms_dir="platforms", required_only=True,
+            )
+        with zipfile.ZipFile(zip_path) as zf:
+            packed = sorted(n for n in zf.namelist() if n != "README.txt")
+        self.assertEqual(packed, held)
+
+    def test_required_only_core_files_keep_one_member(self):
+        from alternatives import core_file_spares
+
+        undeclared = find_undeclared_files(
+            self.config, "emulators", self.db, {"seq": self.profile}
+        )
+        spares = core_file_spares(undeclared)
+        kept = sorted(u["name"] for u in undeclared if id(u) not in spares)
+        self.assertEqual(kept, ["none_a.bin", "plain.bin", "second.bin"])

 if __name__ == "__main__":
    unittest.main()
@@ -36,9 +36,9 @@ class TheGroupFollowsWhatTheProfileSays(unittest.TestCase):
        })
        self.assertEqual(groups, ["clk:file:MSX/msx-american.rom"])

-    def test_a_variant_group_stays_one_slot(self):
+    def test_a_selection_slot_stays_one_slot(self):
        self.assertEqual(
-            extra_region_groups({"source_emulator": "picodrive", "variant_group": "mcd",
+            extra_region_groups({"source_emulator": "picodrive", "selection_slot": "mcd",
                                 "source_systems": ["sega-segacd", "sega-mega-cd"]}),
            ["picodrive:variant:mcd"],
        )
@@ -91,10 +91,10 @@ class TheGroupTakesThePlatformSpelling(unittest.TestCase):
            ["sega-saturn"],
        )

-    def test_file_and_variant_groups_are_untouched(self):
+    def test_file_and_selection_slots_are_untouched(self):
        spellings = system_spellings(["sega-megacd"])
        self.assertEqual(
-            extra_region_groups({"source_emulator": "picodrive", "variant_group": "mcd",
+            extra_region_groups({"source_emulator": "picodrive", "selection_slot": "mcd",
                                 "source_system": "sega-megacd"}, spellings),
            ["picodrive:variant:mcd"],
        )
@@ -275,7 +275,7 @@ own package list, standalone emulators included, and is case-sensitive too, so
 it gets a separate pack and a separate install manifest.
 With `--target`, the fingerprint includes target cores so platforms
 with different hardware filters get separate packs. Emulator and system packs
-also retain system identity, `variant_group` and requested region. Same-named
+also retain system identity, `selection_slot` and requested region. Same-named
 regional files are never collapsed merely because their display label matches.

 ## Pack reproducibility
@@ -603,7 +603,7 @@ look.
 | Field | Description |
 |-------|-------------|
 | `name` | filename as the core expects it |
-| `required` | true if the core needs this file to function. On a member of a `group`, the requirement of the set |
+| `required` | true if the core needs this file to function. Not written on a member of a `group`: derived from the sets in `groups` |
 | `system` | system ID this file belongs to (for multi-system profiles) |
 | `systems` | the systems of the profile this file serves, when it serves several but not all (a MAME device set the machines of two systems load). Never written with `system` |
 | `archive` | ROM set the file lives inside, for arcade entries (e.g. `neogeo.zip`) |
@@ -622,7 +622,8 @@ look.
 | `region_check` | true if the core refuses to boot a game whose region does not match the BIOS |
 | `fast_boot` | BIOS generation label the core uses to decide whether fast boot is available |
 | `priority` | preference order when several BIOS satisfy the same slot, **lowest wins**. DuckStation's `FindBIOSImageInDirectory` keeps the image whose priority is lower, and its table de-prioritizes by raising the number: the buggy launch console sits at 50 and PS2 images at 100, while `scph5501` sits at 5. A core that walks an ordered search list, as PicoDrive does with `biosfiles_us/eu/jp`, maps onto the same field as 1, 2, 3. Only set it from the source. `--one-per-slot` reads it, comparing the members of one `group` |
-| `group` | entries the code takes one of: it loads the first it finds (Yabause tries `saturn_bios.bin`, `sega_101.bin`, `mpr-17933.bin`), and holding any member fills the need. Verify, the gap report and the packs report a set nobody holds as one gap under its first member, and no member of a held set as missing. `required` is the same on every member, the order stays in `priority`. A list puts a file in several sets. Where the code keeps a list per region, each list is its own group (PicoDrive's `mega-cd-us`, `mega-cd-eu`, `mega-cd-jp`) |
+| `group` | the sets of the profile's `groups:` map an entry belongs to. A set is one need: the code loads one member (the first it finds, as Yabause tries `saturn_bios.bin`, `sega_101.bin`, `mpr-17933.bin`) and holding any member fills it. Verify, the gap report and the packs report a set nobody holds as one gap under its first member, and no member of a held set as missing. A `--required-only` build keeps one member per required set, the first the code reads among those held. A list puts a file in several sets, a map from set to rank gives its place in each when it differs (pom2's `apple2.rom` is second for the ][ and third at boot). Where the code keeps a list per region, each list is its own set (PicoDrive's `mega-cd-us`, `mega-cd-eu`, `mega-cd-jp`) |
+| `groups` (profile) | the requirement of each set, `{name: {required: bool}}`. A member writes no `required`: it is required when one of its sets is, so a fallback shared by a required set and an optional one needs no value of its own |
 | `embedded` | true if the data is compiled into the binary and the external file is optional |
 | `bundled` | true if the emulator's own release installs the file where it reads it, for the build `mode` names (all builds when `mode` is absent). Packs and the installer leave it out: the user already has it. A file the standalone release ships but the libretro core does not (PPSSPP's assets, Dolphin's Sys) is bundled with `mode: standalone` only |
 | `not_bundled_on` | platforms (registry keys) whose package leaves out a file the release bundles: their packs bring it (Batocera installs hcl without its data) |
@@ -636,7 +637,7 @@ look.
 | `path` | destination path relative to the system directory, or to the save directory under `load_from: save_dir` |
 | `standalone_path` | where the standalone build reads the file, under its own data folder, when it differs from `path` (the libretro destination). Packs for a platform running the emulator standalone use it |
 | `on_mismatch` | what the code does when a declared check fails: `reject` (default) or `warn` and run with it, for every check or check by check (`{size: warn, md5: reject}`) |
-| `variant_group` | one slot of one core that several entries fill, whatever system each is filed under (PicoDrive's twelve Mega CD BIOS). Region selection keeps one per group |
+| `selection_slot` | files one core chooses between by a rule other than first found (the disc's territory, a core option, a feature probe), one slot of the core whatever system each is filed under: PicoDrive's twelve Mega CD BIOS, picked by disc region, O2EM's four BIOS, picked by a core option. Region selection compares them together and keeps one per slot. A member does not stand in for another: entries that do are a `group` |
 | `size_note` | how the code treats the file's size when no size field can say it (a read capped at 32 bytes, a file created empty when absent) |
 | `type` | `directory` when the code reads a whole tree (an RTP, a folder of speech samples). `path` is then the directory, written with its trailing slash, and the entry stands for every file the collection holds under it. A name ending in `/` requires it |
 | `description` | what this file is |