[romfs] Add romfslite mod folder support (Totk Ultracam) (#2730)

Support the romfslite folder type introduced in Atmosphere 1.9.5 for
memory-optimized mod loading. The emulator now detects and loads
romfslite folders the same way as romfs folders.

Utilised by Ultracam 3.0. Credit to Zephyron (Citron)

Co-authored-by: Zephyron <zephyron@citron-emu.org>

Co-authored-by: Zephyron <zephyron@citron-emu.org>
Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/2730
Reviewed-by: Lizzie <lizzie@eden-emu.dev>
Reviewed-by: MaranBr <maranbr@eden-emu.dev>
Co-authored-by: JPikachu <jpikachu@eden-emu.dev>
Co-committed-by: JPikachu <jpikachu@eden-emu.dev>

2 files changed, 16 insertions, 3 deletions

diff --git a/src/android/app/src/main/java/org/yuzu/yuzu_emu/utils/AddonUtil.kt b/src/android/app/src/main/java/org/yuzu/yuzu_emu/utils/AddonUtil.kt
index 8cc5ea71f2..b5613a7a76 100644
--- a/src/android/app/src/main/java/org/yuzu/yuzu_emu/utils/AddonUtil.kt
+++ b/src/android/app/src/main/java/org/yuzu/yuzu_emu/utils/AddonUtil.kt
@@ -1,8 +1,11 @@
+// SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+// SPDX-License-Identifier: GPL-3.0-or-later
+
 // SPDX-FileCopyrightText: 2023 yuzu Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 package org.yuzu.yuzu_emu.utils
 
 object AddonUtil {
-    val validAddonDirectories = listOf("cheats", "exefs", "romfs")
+    val validAddonDirectories = listOf("cheats", "exefs", "romfs", "romfslite")
 }
diff --git a/src/core/file_sys/patch_manager.cpp b/src/core/file_sys/patch_manager.cpp
index 21d45235e4..11984ca7ca 100644
--- a/src/core/file_sys/patch_manager.cpp
+++ b/src/core/file_sys/patch_manager.cpp
@@ -1,3 +1,6 @@
+// SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+// SPDX-License-Identifier: GPL-3.0-or-later
+
 // SPDX-FileCopyrightText: Copyright 2018 yuzu Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
@@ -379,6 +382,11 @@ static void ApplyLayeredFS(VirtualFile& romfs, u64 title_id, ContentRecordType t
         if (romfs_dir != nullptr)
             layers.emplace_back(std::make_shared<CachedVfsDirectory>(std::move(romfs_dir)));
 
+        // Support for romfslite introduced in Atmosphere 1.9.5
+        auto romfslite_dir = FindSubdirectoryCaseless(subdir, "romfslite");
+        if (romfslite_dir != nullptr)
+            layers.emplace_back(std::make_shared<CachedVfsDirectory>(std::move(romfslite_dir)));
+
         auto ext_dir = FindSubdirectoryCaseless(subdir, "romfs_ext");
         if (ext_dir != nullptr)
             layers_ext.emplace_back(std::make_shared<CachedVfsDirectory>(std::move(ext_dir)));
@@ -537,7 +545,8 @@ std::vector<Patch> PatchManager::GetPatches(VirtualFile update_raw) const {
                 if (layeredfs)
                     AppendCommaIfNotEmpty(types, "LayeredExeFS");
             }
-            if (IsDirValidAndNonEmpty(FindSubdirectoryCaseless(mod, "romfs")))
+            if (IsDirValidAndNonEmpty(FindSubdirectoryCaseless(mod, "romfs")) ||
+                IsDirValidAndNonEmpty(FindSubdirectoryCaseless(mod, "romfslite")))
                 AppendCommaIfNotEmpty(types, "LayeredFS");
             if (IsDirValidAndNonEmpty(FindSubdirectoryCaseless(mod, "cheats")))
                 AppendCommaIfNotEmpty(types, "Cheats");
@@ -563,7 +572,8 @@ std::vector<Patch> PatchManager::GetPatches(VirtualFile update_raw) const {
         if (IsDirValidAndNonEmpty(FindSubdirectoryCaseless(sdmc_mod_dir, "exefs"))) {
             AppendCommaIfNotEmpty(types, "LayeredExeFS");
         }
-        if (IsDirValidAndNonEmpty(FindSubdirectoryCaseless(sdmc_mod_dir, "romfs"))) {
+        if (IsDirValidAndNonEmpty(FindSubdirectoryCaseless(sdmc_mod_dir, "romfs")) ||
+            IsDirValidAndNonEmpty(FindSubdirectoryCaseless(sdmc_mod_dir, "romfslite"))) {
             AppendCommaIfNotEmpty(types, "LayeredFS");
         }