diff --git a/Common/LogManager.cpp b/Common/LogManager.cpp
index 60396a6e27..d7fac46d39 100644
--- a/Common/LogManager.cpp
+++ b/Common/LogManager.cpp
@@ -302,7 +302,9 @@ void LogManager::RemoveListener(LogListener *listener) {
 }
 
 FileLogListener::FileLogListener(const char *filename) {
-	fp_ = File::OpenCFile(Path(std::string(filename)), "at");
+	if (strlen(filename) > 0) {
+		fp_ = File::OpenCFile(Path(std::string(filename)), "at");
+	}
 	SetEnabled(fp_ != nullptr);
 }
 
diff --git a/Common/Net/Sinks.cpp b/Common/Net/Sinks.cpp
index b6453bcf85..62eb407dac 100644
--- a/Common/Net/Sinks.cpp
+++ b/Common/Net/Sinks.cpp
@@ -422,7 +422,7 @@ bool OutputSink::Empty() const {
 	return valid_ == 0;
 }
 
-int OutputSink::BytesRemaining() const {
+size_t OutputSink::BytesRemaining() const {
 	return valid_;
 }
 
diff --git a/Common/Net/Sinks.h b/Common/Net/Sinks.h
index b997abf342..b42c441eb7 100644
--- a/Common/Net/Sinks.h
+++ b/Common/Net/Sinks.h
@@ -55,7 +55,7 @@ public:
 	void Discard();
 
 	bool Empty() const;
-	int BytesRemaining() const;
+	size_t BytesRemaining() const;
 
 private:
 	void Drain();
diff --git a/Core/FileLoaders/DiskCachingFileLoader.cpp b/Core/FileLoaders/DiskCachingFileLoader.cpp
index 9ee0fcabf6..dee0d5a70a 100644
--- a/Core/FileLoaders/DiskCachingFileLoader.cpp
+++ b/Core/FileLoaders/DiskCachingFileLoader.cpp
@@ -692,7 +692,7 @@ bool DiskCachingFileLoaderCache::LockCacheFile(bool lockStatus) {
 	// TODO: Also use flock where supported?
 	if (lockStatus) {
 		if ((flags_ & FLAG_LOCKED) != 0) {
-			ERROR_LOG(LOADER, "Could not lock disk cache file for %s", origPath_.c_str());
+			ERROR_LOG(LOADER, "Could not lock disk cache file for %s (already locked)", origPath_.c_str());
 			return false;
 		}
 		flags_ |= FLAG_LOCKED;
diff --git a/Core/FileSystems/BlockDevices.cpp b/Core/FileSystems/BlockDevices.cpp
index 03fca8d221..e0f1847979 100644
--- a/Core/FileSystems/BlockDevices.cpp
+++ b/Core/FileSystems/BlockDevices.cpp
@@ -621,7 +621,7 @@ CHDFileBlockDevice::CHDFileBlockDevice(FileLoader *fileLoader)
 
 CHDFileBlockDevice::~CHDFileBlockDevice()
 {
-	if (numBlocks > 0) {
+	if (impl_->chd) {
 		chd_close(impl_->chd);
 		delete[] readBuffer;
 	}
@@ -629,6 +629,10 @@ CHDFileBlockDevice::~CHDFileBlockDevice()
 
 bool CHDFileBlockDevice::ReadBlock(int blockNumber, u8 *outPtr, bool uncached)
 {
+	if (!impl_->chd) {
+		ERROR_LOG(LOADER, "ReadBlock: CHD not open. %s", fileLoader_->GetPath().c_str());
+		return false;
+	}
 	if ((u32)blockNumber >= numBlocks) {
 		memset(outPtr, 0, GetBlockSize());
 		return false;
diff --git a/Core/FileSystems/BlockDevices.h b/Core/FileSystems/BlockDevices.h
index 9dca25e8eb..e5f01767c9 100644
--- a/Core/FileSystems/BlockDevices.h
+++ b/Core/FileSystems/BlockDevices.h
@@ -147,10 +147,10 @@ public:
 
 private:
 	std::unique_ptr<CHDImpl> impl_;
-	u8 *readBuffer;
-	u32 currentHunk;
-	u32 blocksPerHunk;
-	u32 numBlocks;
+	u8 *readBuffer = nullptr;
+	u32 currentHunk = 0;
+	u32 blocksPerHunk = 0;
+	u32 numBlocks = 0;
 };
 
 BlockDevice *constructBlockDevice(FileLoader *fileLoader);
diff --git a/Core/System.cpp b/Core/System.cpp
index 8421cb297e..7b157e7fa3 100644
--- a/Core/System.cpp
+++ b/Core/System.cpp
@@ -190,6 +190,12 @@ static bool LoadSymbolsIfSupported() {
 		if (!g_symbolMap)
 			return false;
 
+		if (PSP_CoreParameter().fileToStart.Type() == PathType::HTTP) {
+			// We don't support loading symbols over HTTP.
+			g_symbolMap->Clear();
+			return true;
+		}
+
 		bool result1 = g_symbolMap->LoadSymbolMap(SymbolMapFilename(PSP_CoreParameter().fileToStart, ".ppmap"));
 		// Load the old-style map file.
 		if (!result1)
diff --git a/Core/WebServer.cpp b/Core/WebServer.cpp
index abb03555b9..0310837872 100644
--- a/Core/WebServer.cpp
+++ b/Core/WebServer.cpp
@@ -113,7 +113,9 @@ static bool RegisterServer(int port) {
 
 bool RemoteISOFileSupported(const std::string &filename) {
 	// Disc-like files.
-	if (endsWithNoCase(filename, ".cso") || endsWithNoCase(filename, ".iso") || endsWithNoCase(filename, ".chd")) {
+	// NOTE: chd is temporarily disabled until we can make it use the FileLoader instead of
+	// trying to re-open the file, since otherwise won't work over HTTP.
+	if (endsWithNoCase(filename, ".cso") || endsWithNoCase(filename, ".iso")) {
 		return true;
 	}
 	// May work - but won't have supporting files.