From 6cdf4c28a77af1f3a4431c129bed11895630d83f Mon Sep 17 00:00:00 2001
From: snowstormxd <214507868+snowstormxd@users.noreply.github.com>
Date: Mon, 2 Nov 2026 19:42:01 +0000
Subject: loader: find mixed-case loose RomFS directories consistently

Linux missed base version metadata for Base/RomFS while Windows included it. Use a case-insensitive fallback for the loose directory and check the version and resulting archive checksum.

Assisted by Codex.
---
 src/core/loader/deconstructed_rom_directory.cpp | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

(limited to 'src/core')

diff --git a/src/core/loader/deconstructed_rom_directory.cpp b/src/core/loader/deconstructed_rom_directory.cpp
index 4b1168a59b..49352a5b49 100644
--- a/src/core/loader/deconstructed_rom_directory.cpp
+++ b/src/core/loader/deconstructed_rom_directory.cpp
@@ -81,6 +81,24 @@ struct PatchCollection {
 
 namespace {
 
+FileSys::VirtualDir FindLooseRomFSDirectory(const FileSys::VirtualDir& parent) {
+    if (parent == nullptr) {
+        return nullptr;
+    }
+    if (const auto dir = parent->GetSubdirectory("romfs")) {
+        return dir;
+    }
+    for (const auto& dir : parent->GetSubdirectories()) {
+        const auto name = dir->GetName();
+        if (name.size() == 5 && std::equal(name.begin(), name.end(), "romfs", [](char a, char b) {
+                return std::tolower(static_cast<unsigned char>(a)) == b;
+            })) {
+            return dir;
+        }
+    }
+    return nullptr;
+}
+
 // RomFS for a loose ExeFS: the first .romfs file next to main, else a romfs/ directory next to
 // the exefs/ directory (the usual layout of an extracted title).
 FileSys::VirtualFile FindLooseRomFS(const FileSys::VirtualDir& exefs_dir) {
@@ -93,7 +111,7 @@ FileSys::VirtualFile FindLooseRomFS(const FileSys::VirtualDir& exefs_dir) {
         }
     }
     if (const auto parent = exefs_dir->GetParentDirectory()) {
-        if (const auto romfs_dir = parent->GetSubdirectory("romfs")) {
+        if (const auto romfs_dir = FindLooseRomFSDirectory(parent)) {
             // Building it walks every file and keeps an object for each (title 1: 206k files, ~150
             // MiB), so loaders of the same directory share one build while any of them holds it.
             static std::mutex cache_mutex;
@@ -268,7 +286,7 @@ AppLoader_DeconstructedRomDirectory::AppLoader_DeconstructedRomDirectory(FileSys
 
     romfs_exefs_dir = file_dir;
     if (const auto title_dir = file_dir->GetParentDirectory()) {
-        romfs_version = RomFSProductVersion(title_dir->GetSubdirectory("romfs"));
+        romfs_version = RomFSProductVersion(FindLooseRomFSDirectory(title_dir));
     }
 }
 
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