fix: tag regions by the branch the code takes

Mega CD US BIOS serves every non-EU, non-JP disc; Dolphin boots
Korean discs from the JAP directory; Beetle never opens scph5903.bin
under that name.

emulators/beetle_psx.yml

@@ -45,8 +45,8 @@ files:
 
   - name: "scph5903.bin"
     description: "SCPH-5903 (System ROM Version 2.2 12/04/95 J), Video CD daughterboard"
-    region: [japan]
     required: false
+    note: "No code path opens this name: the Japanese name list and the SHA-1 scan look for scph5500.bin (libretro.c:594-602, 486-490). Copied as scph5500.bin it loads with a SHA-1 warning (libretro.c:680-687) and enables the Video CD daughterboard."
     size: 1048576
     sha1: "15c94da3cc5a38a582429575af4198c487fe893c"
     md5: "81328b966e6dcf7ea1e32e55e1c104bb"

emulators/dolphin-mmjr.yml

@@ -111,7 +111,7 @@ files:
     system: nintendo-gamecube
     required: false
     hle_fallback: true
-    region: [japan]
+    region: [japan, south-korea]
     size: 2097152
     crc32: ["6dac1f2a", "d5e6feea", "86573808", "667d0b64"]
     validation: [crc32]

emulators/dolphin-mmjr2.yml

@@ -147,7 +147,7 @@ files:
     system: nintendo-gamecube
     required: false
     hle_fallback: true
-    region: [japan]
+    region: [japan, south-korea]
     size: 2097152
     crc32: ["6dac1f2a", "d5e6feea", "86573808", "667d0b64"]
     validation: [crc32]

emulators/dolphin.yml

@@ -58,7 +58,7 @@ files:
   - name: "IPL.bin"
     path: "dolphin-emu/Sys/GC/JAP/IPL.bin"
     standalone_path: "GC/JAP/IPL.bin"
-    region: [japan]
+    region: [japan, south-korea]
     size: 2097152
     required: false
     hle_fallback: true

emulators/genesis_plus_gx.yml

@@ -40,9 +40,9 @@ files:
   # -------------------------------------------------------
   - name: bios_CD_U.bin
     system: sega-megacd
-    region: [north-america]
+    region: [north-america, latin-america]
     required: true
-    note: "Sega CD (NTSC-U) boot ROM. Loaded for REGION_USA."
+    note: "Sega CD (NTSC-U) boot ROM. Loaded for REGION_USA, which get_region sets for every disc whose security byte is neither 0x64 (Europe) nor 0xa1 (Japan) (core/loadrom.c:1065-1078)."
     source_ref: "core/loadrom.c:409"
 
   - name: bios_CD_E.bin

emulators/genesis_plus_gx_wide.yml

@@ -27,7 +27,7 @@ notes: |
 files:
   - name: bios_CD_U.bin
     system: sega-megacd
-    region: [north-america]
+    region: [north-america, latin-america]
     required: true
     size: 131072
     source_ref: "core/loadrom.c:408"

emulators/ishiiruka.yml

@@ -55,7 +55,7 @@ files:
   - name: "IPL.bin"
     path: "dolphin-emu/Sys/GC/JAP/IPL.bin"
     standalone_path: "GC/JAP/IPL.bin"
-    region: [japan]
+    region: [japan, south-korea]
     size: 2097152
     required: false
     hle_fallback: true

emulators/picodrive.yml

@@ -65,17 +65,17 @@ files:
   - name: "us_scd2_9306.bin"
     system: sega-megacd
     variant_group: "mega-cd-bios"
-    region: [north-america]
+    region: [north-america, latin-america]
     priority: 1
     required: true
     size: 131072  # 128 KB (0x20000)
-    note: "US Sega CD Model 2 BIOS (September 1993). First in US search order."
+    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: "platform/libretro/libretro.c:1273"
 
   - name: "SegaCDBIOS9303.bin"
     system: sega-megacd
     variant_group: "mega-cd-bios"
-    region: [north-america]
+    region: [north-america, latin-america]
     priority: 2
     required: false
     size: 131072
@@ -85,7 +85,7 @@ files:
   - name: "us_scd1_9210.bin"
     system: sega-megacd
     variant_group: "mega-cd-bios"
-    region: [north-america]
+    region: [north-america, latin-america]
     priority: 3
     required: false
     size: 131072
@@ -95,7 +95,7 @@ files:
   - name: "bios_CD_U.bin"
     system: sega-megacd
     variant_group: "mega-cd-bios"
-    region: [north-america]
+    region: [north-america, latin-america]
     priority: 4
     required: false
     size: 131072

emulators/primehack.yml

@@ -52,7 +52,7 @@ files:
 
   - name: "IPL.bin"
     path: "GC/JAP/IPL.bin"
-    region: [japan]
+    region: [japan, south-korea]
     size: 2097152
     required: false
     hle_fallback: true

emulators/triforce.yml

@@ -141,7 +141,7 @@ files:
     path: "GC/JAP/IPL_TRI.bin"
     description: "Triforce boot ROM, NTSC-J directory"
     system: sega-triforce
-    region: [japan]
+    region: [japan, south-korea]
     size: 2097152
     crc32: "d1883221"
     validation: [crc32]
@@ -214,7 +214,7 @@ files:
   - name: "IPL.bin"
     path: "GC/JAP/IPL.bin"
     description: "GameCube NTSC-J boot ROM"
-    region: [japan]
+    region: [japan, south-korea]
     size: 2097152
     required: false
     hle_fallback: true