fix: hold installer detection to the registry

install.ps1

@@ -8,7 +8,7 @@ param(
 
 $ErrorActionPreference = "Stop"
 $defaultInstallUrl = "https://raw.githubusercontent.com/Abdess/retrobios/main/install.py"
-$defaultInstallSha256 = "8faaf944ff4e0cc23e9049299145077567163837eaabdd65c530554980080ed7"
+$defaultInstallSha256 = "236441baeb94f442c15a93ac01a203ce63f2938553b491db13dfb19074bbef46"
 $maximumInstallerBytes = 2MB
 $installerExit = 0
 $installer = if ($PSScriptRoot) { Join-Path $PSScriptRoot "install.py" } else { $null }

install.py

@@ -621,55 +621,34 @@ def _parse_ps1_var(path: Path, key: str) -> str | None:
     return None
 
 
+# Embedded systems, first match wins: Knulli also carries the Batocera
+# markers. The registry publishes the same rules as each manifest's
+# `detect`; a test holds the two equal. MiSTer is a path rule below.
+_EMBEDDED_RULES: tuple[tuple[str, str, tuple[str, ...], str], ...] = (
+    ("rocknix", "os_release", ("rocknix",), "/storage/roms/bios"),
+    ("batocera", "file_exists", ("/etc/knulli-release",), "/userdata/bios"),
+    ("lakka", "os_release", ("lakka",), "/storage/system"),
+    ("batocera", "file_exists", ("/etc/batocera-version",), "/userdata/bios"),
+    ("recalbox", "file_exists", ("/recalbox/recalbox.version",), "/recalbox/share/bios"),
+    ("recalbox", "file_exists", ("/usr/bin/recalbox-settings",), "/recalbox/share/bios"),
+    ("retroarch", "file_exists", ("/opt/muos",), "/mnt/mmc/MUOS/bios"),
+    ("retroarch", "file_exists", ("/mnt/mmc/MUOS",), "/mnt/mmc/MUOS/bios"),
+    ("retroarch", "file_exists", ("/home/ark", "/opt/system"), "/roms/bios"),
+    ("retroarch", "file_exists", ("/mnt/vendor/bin/dmenu.bin",), "/mnt/mmc/bios"),
+)
+
+
 def _detect_embedded() -> list[tuple[str, Path]]:
     """Check for embedded Linux retrogaming OSes."""
-    found: list[tuple[str, Path]] = []
-    os_release = _parse_os_release()
-    os_id = os_release.get("ID", "").lower()
-
-    if os_id == "rocknix":
-        found.append(("rocknix", Path("/storage/roms/bios")))
-        return found
-
-    # MiSTer keeps the SD card at /media/fat with the main binary at its root
-    # (Main_MiSTer file_io.cpp:1150-1156), and cores read from games/
-    # (file_io.h:168)
-    if Path("/media/fat/MiSTer").exists():
-        found.append(("misterfpga", Path("/media/fat/games")))
-        return found
-
-    if Path("/etc/knulli-release").exists():
-        found.append(("batocera", Path("/userdata/bios")))
-        return found
-
-    if os_id == "lakka":
-        found.append(("lakka", Path("/storage/system")))
-        return found
-
-    if Path("/etc/batocera-version").exists():
-        found.append(("batocera", Path("/userdata/bios")))
-        return found
-
-    if (
-        Path("/recalbox/recalbox.version").exists()
-        or Path("/usr/bin/recalbox-settings").exists()
-    ):
-        found.append(("recalbox", Path("/recalbox/share/bios")))
-        return found
-
-    if Path("/opt/muos").exists() or Path("/mnt/mmc/MUOS/").exists():
-        found.append(("retroarch", Path("/mnt/mmc/MUOS/bios")))
-        return found
-
-    if Path("/home/ark").exists() and Path("/opt/system").exists():
-        found.append(("retroarch", Path("/roms/bios")))
-        return found
-
-    if Path("/mnt/vendor/bin/dmenu.bin").exists():
-        found.append(("retroarch", Path("/mnt/mmc/bios")))
-        return found
-
-    return found
+    os_id = _parse_os_release().get("ID", "").lower()
+    for platform_name, method, values, bios in _EMBEDDED_RULES:
+        if method == "os_release":
+            matched = os_id in values
+        else:
+            matched = all(Path(value).exists() for value in values)
+        if matched:
+            return [(platform_name, Path(bios))]
+    return []
 
 
 def _android_storage_root() -> Path:

install.sh

@@ -18,7 +18,7 @@ esac
 TEMP_INSTALLER=""
 TEMP_DIRECTORY=""
 DEFAULT_INSTALL_URL="https://raw.githubusercontent.com/Abdess/retrobios/main/install.py"
-DEFAULT_INSTALL_SHA256="8faaf944ff4e0cc23e9049299145077567163837eaabdd65c530554980080ed7"
+DEFAULT_INSTALL_SHA256="236441baeb94f442c15a93ac01a203ce63f2938553b491db13dfb19074bbef46"
 MAX_INSTALLER_BYTES=2097152
 
 cleanup() {

install/batocera.json

@@ -8,6 +8,12 @@
   "generated": "2026-10-18T11:24:19Z",
   "base_destination": "bios",
   "detect": [
+    {
+      "os": "linux",
+      "method": "file_exists",
+      "file": "/etc/knulli-release",
+      "bios_path": "/userdata/bios"
+    },
     {
       "os": "linux",
       "method": "file_exists",

install/recalbox.json

@@ -8,6 +8,12 @@
   "generated": "2026-10-18T11:24:19Z",
   "base_destination": "bios",
   "detect": [
+    {
+      "os": "linux",
+      "method": "file_exists",
+      "file": "/recalbox/recalbox.version",
+      "bios_path": "/recalbox/share/bios"
+    },
     {
       "os": "linux",
       "method": "file_exists",

install/retroarch.json

@@ -38,6 +38,33 @@
       "method": "config_file",
       "config": "%APPDATA%\\RetroArch\\retroarch.cfg",
       "parse_key": "system_directory"
+    },
+    {
+      "os": "linux",
+      "method": "file_exists",
+      "file": "/opt/muos",
+      "bios_path": "/mnt/mmc/MUOS/bios"
+    },
+    {
+      "os": "linux",
+      "method": "file_exists",
+      "file": "/mnt/mmc/MUOS",
+      "bios_path": "/mnt/mmc/MUOS/bios"
+    },
+    {
+      "os": "linux",
+      "method": "file_exists",
+      "file": [
+        "/home/ark",
+        "/opt/system"
+      ],
+      "bios_path": "/roms/bios"
+    },
+    {
+      "os": "linux",
+      "method": "file_exists",
+      "file": "/mnt/vendor/bin/dmenu.bin",
+      "bios_path": "/mnt/mmc/bios"
     }
   ],
   "standalone_copies": [

install/rocknix.json

@@ -10,9 +10,8 @@
   "detect": [
     {
       "os": "linux",
-      "method": "file_exists",
-      "file": "/etc/os-release",
-      "match": "ID=rocknix",
+      "method": "os_release",
+      "id": "rocknix",
       "bios_path": "/storage/roms/bios"
     }
   ],

platforms/_registry.yml

@@ -187,6 +187,24 @@ platforms:
         method: config_file
         config: '%APPDATA%\RetroArch\retroarch.cfg'
         parse_key: system_directory
+      # Handheld firmwares that run RetroArch as their frontend: muOS,
+      # ArkOS, and the stock Linux of Anbernic devices (dmenu).
+      - os: linux
+        method: file_exists
+        file: /opt/muos
+        bios_path: /mnt/mmc/MUOS/bios
+      - os: linux
+        method: file_exists
+        file: /mnt/mmc/MUOS
+        bios_path: /mnt/mmc/MUOS/bios
+      - os: linux
+        method: file_exists
+        file: [/home/ark, /opt/system]
+        bios_path: /roms/bios
+      - os: linux
+        method: file_exists
+        file: /mnt/vendor/bin/dmenu.bin
+        bios_path: /mnt/mmc/bios
       standalone_copies: *standalone_copies
   batocera:
     config: batocera.yml
@@ -202,6 +220,11 @@ platforms:
     target_source: https://github.com/batocera-linux/batocera.linux
     install:
       detect:
+      # Knulli is a Batocera derivative and carries its markers too.
+      - os: linux
+        method: file_exists
+        file: /etc/knulli-release
+        bios_path: /userdata/bios
       - os: linux
         method: file_exists
         file: /etc/batocera-version
@@ -223,6 +246,10 @@ platforms:
     target_source: https://gitlab.com/recalbox/recalbox/-/tree/master/configs
     install:
       detect:
+      - os: linux
+        method: file_exists
+        file: /recalbox/recalbox.version
+        bios_path: /recalbox/share/bios
       - os: linux
         method: file_exists
         file: /usr/bin/recalbox-settings
@@ -388,9 +415,8 @@ platforms:
     install:
       detect:
       - os: linux
-        method: file_exists
-        file: /etc/os-release
-        match: 'ID=rocknix'
+        method: os_release
+        id: rocknix
         bios_path: /storage/roms/bios
   retropie:
     config: retropie.yml

tests/test_install.py

@@ -264,10 +264,15 @@ class TestEmbeddedDetection(unittest.TestCase):
             install._parse_os_release = real_parse
 
     def test_mister_detected_from_main_binary(self):
-        self.assertEqual(
-            self._detect_with({"/media/fat/MiSTer"}),
-            [("misterfpga", Path("/media/fat/games"))],
-        )
+        # A path rule of the registry, read by _detect_by_path.
+        real_exists = install.Path.exists
+        install.Path.exists = lambda self: str(self) == "/media/fat/MiSTer"
+        try:
+            found: list = []
+            install._detect_by_path("linux", found)
+        finally:
+            install.Path.exists = real_exists
+        self.assertEqual(found, [("misterfpga", Path("/media/fat/games"))])
 
     def test_rocknix_wins_over_path_probes(self):
         self.assertEqual(
@@ -940,6 +945,38 @@ class DetectionFollowsTheRegistry(unittest.TestCase):
         }
         self.assertEqual(set(install._PATH_RULES), rules)
 
+    def test_the_embedded_table_is_the_registry(self):
+        """Only the path rules were compared: Knulli, muOS, ArkOS and the
+        Recalbox version file were detected by the installer and absent
+        from every manifest's `detect`, and ROCKNIX was declared another
+        way. A changed bios_path in the registry reached no installer."""
+        import yaml  # noqa: PLC0415
+
+        registry = yaml.safe_load(
+            (Path(__file__).resolve().parents[1] / "platforms" / "_registry.yml").read_text()
+        )
+        rules = set()
+        for name, entry in registry["platforms"].items():
+            for rule in (entry.get("install") or {}).get("detect", []):
+                if rule["method"] == "os_release":
+                    rules.add((name, "os_release", (rule["id"],), rule["bios_path"]))
+                elif rule["method"] == "file_exists":
+                    files = rule["file"] if isinstance(rule["file"], list) else [rule["file"]]
+                    rules.add((name, "file_exists", tuple(files), rule["bios_path"]))
+        self.assertEqual(set(install._EMBEDDED_RULES), rules)
+
+    def test_the_first_embedded_match_wins(self):
+        with unittest.mock.patch.object(install, "_parse_os_release", return_value={}), \
+                unittest.mock.patch.object(
+                    Path, "exists",
+                    lambda p: str(p) in ("/etc/knulli-release", "/etc/batocera-version"),
+                ):
+            self.assertEqual(install._detect_embedded(), [("batocera", Path("/userdata/bios"))])
+        with unittest.mock.patch.object(install, "_parse_os_release", return_value={"ID": "ROCKNIX"}):
+            self.assertEqual(
+                install._detect_embedded(), [("rocknix", Path("/storage/roms/bios"))]
+            )
+
     def _home(self) -> Path:
         home = Path(_tempdir(self))
         patcher = unittest.mock.patch.dict(os.environ, {"HOME": str(home), "USERPROFILE": str(home)})