From 8ddd5f21b6bd7bef1655f929e43f4a017f75d5b8 Mon Sep 17 00:00:00 2001
From: p33k-a-b00 <43139100+p33k-a-b00@users.noreply.github.com>
Date: Sat, 11 Apr 2026 21:36:13 -0400
Subject: [PATCH] FSC: Retry WUA lookup with percent-encoded '@'

Some WUA packers percent-encode reserved characters in entry names, so
'@bg0010.arc' ends up stored as '%40bg0010.arc'. ZArchive's LookUp is
byte-literal, so the initial query misses and FSOpenFile returns -6.

Fixes Twilight Princess HD, whose DVD thread (mDoDvdThd_mountArchive_c)
uses '@'-prefixed archive names for Forest Temple room backgrounds.
Without the retry, the cage room (bg0010) fails to mount and the player
is softlocked on the monkey puzzle.
---
 src/Cafe/Filesystem/fscDeviceWua.cpp | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/src/Cafe/Filesystem/fscDeviceWua.cpp b/src/Cafe/Filesystem/fscDeviceWua.cpp
index f9014bdb..ac15646c 100644
--- a/src/Cafe/Filesystem/fscDeviceWua.cpp
+++ b/src/Cafe/Filesystem/fscDeviceWua.cpp
@@ -125,6 +125,23 @@ class fscDeviceWUAC : public fscDeviceC
 		cemu_assert_debug(!HAS_FLAG(accessFlags, FSC_ACCESS_FLAG::WRITE_PERMISSION)); // writing to WUA is not supported
 
 		ZArchiveNodeHandle fileHandle = archive->LookUp(path, true, true);
+		if (fileHandle == ZARCHIVE_INVALID_NODE && path.find('@') != std::string_view::npos)
+		{
+			// Some WUA packers percent-encode '@' in entry names (stored as "%40"),
+			// so a byte-literal LookUp for "@bg0010.arc" misses "%40bg0010.arc".
+			// Retry with '@' percent-encoded. Affects Twilight Princess HD, whose
+			// DVD thread uses '@'-prefixed archive names for Forest Temple rooms.
+			std::string retryPath;
+			retryPath.reserve(path.size() + 16);
+			for (char c : path)
+			{
+				if (c == '@')
+					retryPath += "%40";
+				else
+					retryPath += c;
+			}
+			fileHandle = archive->LookUp(retryPath, true, true);
+		}
 		if (fileHandle == ZARCHIVE_INVALID_NODE)
 		{
 			*fscStatus = FSC_STATUS_FILE_NOT_FOUND;