diff --git a/install.ps1 b/install.ps1
index 2a57af8b..7a980f89 100644
--- a/install.ps1
+++ b/install.ps1
@@ -8,7 +8,7 @@ param(
 
 $ErrorActionPreference = "Stop"
 $defaultInstallUrl = "https://raw.githubusercontent.com/Abdess/retrobios/main/install.py"
-$defaultInstallSha256 = "dc6b428278a4352923c19ddcf055fd994aac1df77f35cb1d097e8f4c5d887ae1"
+$defaultInstallSha256 = "973e116ab59e233cd4fe5ebb77d4973bc06013b22b6388e80d12fa1d61fb0c73"
 $maximumInstallerBytes = 2MB
 $installerExit = 0
 $installer = if ($PSScriptRoot) { Join-Path $PSScriptRoot "install.py" } else { $null }
diff --git a/install.py b/install.py
index 7dacd8aa..091af425 100644
--- a/install.py
+++ b/install.py
@@ -175,7 +175,6 @@ def _os_default_dests(os_type: str) -> dict[str, Path]:
     home = Path.home()
     if os_type == "windows":
         profile = Path(os.environ.get("USERPROFILE", str(home)))
-        appdata = Path(os.environ.get("APPDATA", str(home / "AppData" / "Roaming")))
         return {
             # RetroArch's system directory defaults to <exe folder>\system
             # (platform_win32.c), and its installer to C:\RetroArch-Win64.
@@ -904,11 +903,11 @@ def _rule_path(template: str) -> Path:
 def _detect_by_path(os_type: str, found: list[tuple[str, Path]]) -> None:
     """Add what a registry path rule finds, for a platform not found yet."""
     systems = ("linux", "windows") if os_type == "wsl" else (os_type,)
-    for rule_os, platform, path, bios in _PATH_RULES:
-        if rule_os not in systems or any(name == platform for name, _ in found):
+    for rule_os, platform_name, path, bios in _PATH_RULES:
+        if rule_os not in systems or any(name == platform_name for name, _ in found):
             continue
         if _rule_path(path).exists():
-            found.append((platform, _rule_path(bios or path)))
+            found.append((platform_name, _rule_path(bios or path)))
 
 
 def detect_platforms(os_type: str) -> list[tuple[str, Path]]:
diff --git a/install.sh b/install.sh
index 097e4551..18daa8a3 100755
--- a/install.sh
+++ b/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="dc6b428278a4352923c19ddcf055fd994aac1df77f35cb1d097e8f4c5d887ae1"
+DEFAULT_INSTALL_SHA256="973e116ab59e233cd4fe5ebb77d4973bc06013b22b6388e80d12fa1d61fb0c73"
 MAX_INSTALLER_BYTES=2097152
 
 cleanup() {
diff --git a/tests/test_install.py b/tests/test_install.py
index f5caf519..0f272cba 100644
--- a/tests/test_install.py
+++ b/tests/test_install.py
@@ -1151,6 +1151,52 @@ class InstallerStaysOnPython38AndTheStdlib(unittest.TestCase):
         self.assertEqual(used, [])
 
 
+    def test_no_local_is_assigned_and_never_read(self):
+        """ruff --select F in py38 mode is the installer's lint gate; an
+        unread `appdata` in _os_default_dests made it exit 1. The suite has
+        no ruff, so the rule is read from the syntax tree."""
+        import ast  # noqa: PLC0415
+
+        tree = ast.parse((Path(__file__).resolve().parents[1] / "install.py").read_text())
+        unread = []
+        for func in ast.walk(tree):
+            if not isinstance(func, (ast.FunctionDef, ast.AsyncFunctionDef)):
+                continue
+            stored, loaded = {}, set()
+            for node in ast.walk(func):
+                if isinstance(node, ast.Name):
+                    if isinstance(node.ctx, ast.Store):
+                        stored.setdefault(node.id, node.lineno)
+                    else:
+                        loaded.add(node.id)
+            nested = {
+                n.id for inner in ast.walk(func) if inner is not func
+                and isinstance(inner, (ast.FunctionDef, ast.Lambda))
+                for n in ast.walk(inner) if isinstance(n, ast.Name)
+            }
+            unread += [
+                f"{func.name}:{line} {name}" for name, line in stored.items()
+                if name not in loaded | nested and not name.startswith("_")
+                and not any(
+                    isinstance(g, (ast.Global, ast.Nonlocal)) and name in g.names
+                    for g in ast.walk(func)
+                )
+            ]
+        self.assertEqual(unread, [])
+        # Nor a module rebound: a loop variable named `platform` shadowed the
+        # platform module in _detect_by_path (F402).
+        modules = {
+            alias.asname or alias.name.split(".")[0]
+            for node in tree.body if isinstance(node, ast.Import)
+            for alias in node.names
+        }
+        rebound = sorted(
+            f"{node.id}:{node.lineno}" for node in ast.walk(tree)
+            if isinstance(node, ast.Name) and isinstance(node.ctx, ast.Store)
+            and node.id in modules
+        )
+        self.assertEqual(rebound, [])
+
 class ARefusedCopyIsAnError(unittest.TestCase):
     """A PermissionError on a standalone copy was counted as "dir not found"
     and the run ended on Done with exit code 0."""