diff --git a/common/FileSystem.cpp b/common/FileSystem.cpp
index 66cc4f57c208c..e162a555999c1 100644
--- a/common/FileSystem.cpp
+++ b/common/FileSystem.cpp
@@ -994,6 +994,37 @@ std::FILE* FileSystem::OpenCFile(const char* filename, const char* mode, Error*
 #endif
 }
 
+std::FILE* FileSystem::OpenCFileTryIgnoreCase(const char* filename, const char* mode, Error* error)
+{
+#if defined(_WIN32) || defined(__APPLE__)
+	return OpenCFile(filename, mode, error);
+#else
+	std::FILE* fp = std::fopen(filename, mode);
+	const auto cur_errno = errno;
+
+	if (!fp)
+	{
+		const auto dir = std::string(Path::GetDirectory(filename));
+		FindResultsArray files;
+		if (FindFiles(dir.c_str(), "*", FILESYSTEM_FIND_FILES | FILESYSTEM_FIND_HIDDEN_FILES, &files))
+		{
+			for (auto& file : files)
+			{
+				if (StringUtil::compareNoCase(file.FileName, filename))
+				{
+					fp = std::fopen(file.FileName.c_str(), mode);
+					break;
+				}
+			}
+		}
+	}
+	if (!fp)
+		Error::SetErrno(error, cur_errno);
+	return fp;
+#endif
+}
+
+
 int FileSystem::OpenFDFile(const char* filename, int flags, int mode, Error* error)
 {
 #ifdef _WIN32
@@ -1015,6 +1046,11 @@ FileSystem::ManagedCFilePtr FileSystem::OpenManagedCFile(const char* filename, c
 	return ManagedCFilePtr(OpenCFile(filename, mode, error));
 }
 
+FileSystem::ManagedCFilePtr FileSystem::OpenManagedCFileTryIgnoreCase(const char* filename, const char* mode, Error* error)
+{
+	return ManagedCFilePtr(OpenCFileTryIgnoreCase(filename, mode, error));
+}
+
 std::FILE* FileSystem::OpenSharedCFile(const char* filename, const char* mode, FileShareMode share_mode, Error* error)
 {
 #ifdef _WIN32
diff --git a/common/FileSystem.h b/common/FileSystem.h
index e1f73229dbcac..6b7fe1806c9b0 100644
--- a/common/FileSystem.h
+++ b/common/FileSystem.h
@@ -106,7 +106,16 @@ namespace FileSystem
 	/// open files
 	using ManagedCFilePtr = std::unique_ptr<std::FILE, FileDeleter>;
 	ManagedCFilePtr OpenManagedCFile(const char* filename, const char* mode, Error* error = nullptr);
+	// Tries to open a file using the given filename, but if that fails searches
+	// the directory for a file with a case-insensitive match.
+	// This is the same as OpenManagedCFile on Windows and MacOS
+	ManagedCFilePtr OpenManagedCFileTryIgnoreCase(const char* filename, const char* mode, Error* error = nullptr);
 	std::FILE* OpenCFile(const char* filename, const char* mode, Error* error = nullptr);
+	// Tries to open a file using the given filename, but if that fails searches
+	// the directory for a file with a case-insensitive match.
+	// This is the same as OpenCFile on Windows and MacOS
+	std::FILE* OpenCFileTryIgnoreCase(const char* filename, const char* mode, Error* error = nullptr);
+
 	int FSeek64(std::FILE* fp, s64 offset, int whence);
 	s64 FTell64(std::FILE* fp);
 	s64 FSize64(std::FILE* fp);
diff --git a/pcsx2/CDVD/CDVD.cpp b/pcsx2/CDVD/CDVD.cpp
index 34bea0e58f07b..9bd3c9b3bf3d8 100644
--- a/pcsx2/CDVD/CDVD.cpp
+++ b/pcsx2/CDVD/CDVD.cpp
@@ -155,7 +155,7 @@ void cdvdLoadNVRAM()
 {
 	Error error;
 	const std::string nvmfile = cdvdGetNVRAMPath();
-	auto fp = FileSystem::OpenManagedCFile(nvmfile.c_str(), "rb", &error);
+	auto fp = FileSystem::OpenManagedCFileTryIgnoreCase(nvmfile.c_str(), "rb", &error);
 	if (!fp || std::fread(s_nvram, sizeof(s_nvram), 1, fp.get()) != 1)
 	{
 		ERROR_LOG("Failed to open or read NVRAM at {}: {}", Path::GetFileName(nvmfile), error.GetDescription());
@@ -178,7 +178,7 @@ void cdvdLoadNVRAM()
 
 	// Also load the mechacon version while we're here.
 	const std::string mecfile = Path::ReplaceExtension(BiosPath, "mec");
-	fp = FileSystem::OpenManagedCFile(mecfile.c_str(), "rb", &error);
+	fp = FileSystem::OpenManagedCFileTryIgnoreCase(mecfile.c_str(), "rb", &error);
 	if (!fp || std::fread(&s_mecha_version, sizeof(s_mecha_version), 1, fp.get()) != 1)
 	{
 		s_mecha_version = DEFAULT_MECHA_VERSION;
@@ -186,7 +186,7 @@ void cdvdLoadNVRAM()
 		ERROR_LOG("Failed to open or read MEC file at {}: {}, creating default.", Path::GetFileName(nvmfile),
 			error.GetDescription());
 		fp.reset();
-		fp = FileSystem::OpenManagedCFile(mecfile.c_str(), "wb");
+		fp = FileSystem::OpenManagedCFileTryIgnoreCase(mecfile.c_str(), "wb");
 		if (!fp || std::fwrite(&s_mecha_version, sizeof(s_mecha_version), 1, fp.get()) != 1)
 			Host::ReportErrorAsync("Error", "Failed to write MEC file. Check your BIOS setup/permission settings.");
 	}
@@ -197,10 +197,10 @@ void cdvdSaveNVRAM()
 {
 	Error error;
 	const std::string nvmfile = cdvdGetNVRAMPath();
-	auto fp = FileSystem::OpenManagedCFile(nvmfile.c_str(), "r+b", &error);
+	auto fp = FileSystem::OpenManagedCFileTryIgnoreCase(nvmfile.c_str(), "r+b", &error);
 	if (!fp)
 	{
-		fp = FileSystem::OpenManagedCFile(nvmfile.c_str(), "w+b", &error);
+		fp = FileSystem::OpenManagedCFileTryIgnoreCase(nvmfile.c_str(), "w+b", &error);
 		if (!fp) [[unlikely]]
 		{
 			ERROR_LOG("Failed to open NVRAM at {} for updating: {}", Path::GetFileName(nvmfile), error.GetDescription());
diff --git a/pcsx2/CDVD/ChdFileReader.cpp b/pcsx2/CDVD/ChdFileReader.cpp
index 8cdb7e4193ad0..a58f24590b5b1 100644
--- a/pcsx2/CDVD/ChdFileReader.cpp
+++ b/pcsx2/CDVD/ChdFileReader.cpp
@@ -105,7 +105,7 @@ static chd_file* OpenCHD(const std::string& filename, FileSystem::ManagedCFilePt
 			parent_dir.c_str(), "*.*", FILESYSTEM_FIND_FILES | FILESYSTEM_FIND_HIDDEN_FILES | FILESYSTEM_FIND_KEEP_ARRAY, &parent_files);
 		for (FILESYSTEM_FIND_DATA& fd : parent_files)
 		{
-			if (StringUtil::EndsWithNoCase(Path::GetExtension(fd.FileName), ".chd"))
+			if (!StringUtil::EndsWithNoCase(Path::GetExtension(fd.FileName), "chd"))
 				continue;
 
 			// Re-check the header, it might have changed since we last opened.
diff --git a/pcsx2/ps2/BiosTools.cpp b/pcsx2/ps2/BiosTools.cpp
index 3604aef71788d..0f3f9a33c0f82 100644
--- a/pcsx2/ps2/BiosTools.cpp
+++ b/pcsx2/ps2/BiosTools.cpp
@@ -226,7 +226,7 @@ static void LoadExtraRom(const char* ext, u32 offset, u32 size)
 
 	BiosRom.resize(offset + size);
 
-	auto fp = FileSystem::OpenManagedCFile(Bios1.c_str(), "rb");
+	auto fp = FileSystem::OpenManagedCFileTryIgnoreCase(Bios1.c_str(), "rb");
 	if (!fp || std::fread(&BiosRom[offset], static_cast<size_t>(std::min<s64>(size, filesize)), 1, fp.get()) != 1)
 	{
 		Console.Warning("BIOS Warning: %s could not be read (permission denied?)", ext);