diff --git a/UI/EmuScreen.cpp b/UI/EmuScreen.cpp
index d9ba778f1b..3d4c791cd2 100644
--- a/UI/EmuScreen.cpp
+++ b/UI/EmuScreen.cpp
@@ -157,6 +157,9 @@ bool EmuScreen::bootAllowStorage(const std::string &filename) {
 	case PERMISSION_STATUS_GRANTED:
 		return true;
 	}
+
+	_assert_(false);
+	return false;
 }
 
 void EmuScreen::bootGame(const std::string &filename) {
diff --git a/android/jni/app-android.cpp b/android/jni/app-android.cpp
index 9ebb82dc0b..602bfd0025 100644
--- a/android/jni/app-android.cpp
+++ b/android/jni/app-android.cpp
@@ -551,7 +551,6 @@ extern "C" void Java_org_ppsspp_ppsspp_NativeRenderer_displayInit(JNIEnv * env,
 	if (renderer_inited) {
 		// Would be really nice if we could get something on the GL thread immediately when shutting down...
 		ILOG("NativeApp.displayInit() restoring");
-		graphicsContext->ThreadEnd();
 		if (useCPUThread) {
 			EmuThreadStop();
 			while (graphicsContext->ThreadFrame()) {
@@ -561,6 +560,7 @@ extern "C" void Java_org_ppsspp_ppsspp_NativeRenderer_displayInit(JNIEnv * env,
 		} else {
 			NativeShutdownGraphics();
 		}
+		graphicsContext->ThreadEnd();
 		graphicsContext->ShutdownFromRenderThread();
 
 		ILOG("Shut down both threads. Now let's bring it up again!");
diff --git a/ext/native/thin3d/GLRenderManager.cpp b/ext/native/thin3d/GLRenderManager.cpp
index 94b5e7b664..32936bd4be 100644
--- a/ext/native/thin3d/GLRenderManager.cpp
+++ b/ext/native/thin3d/GLRenderManager.cpp
@@ -13,6 +13,11 @@
 #define VLOG(...)
 #endif
 
+static std::thread::id renderThreadId;
+static bool OnRenderThread() {
+	return std::this_thread::get_id() == renderThreadId;
+}
+
 // Runs on the GPU thread.
 void GLDeleter::Perform(GLRenderManager *renderManager) {
 	for (auto pushBuffer : pushBuffers) {
@@ -65,6 +70,7 @@ GLRenderManager::~GLRenderManager() {
 void GLRenderManager::ThreadStart() {
 	queueRunner_.CreateDeviceObjects();
 	threadFrame_ = threadInitFrame_;
+	renderThreadId = std::this_thread::get_id();
 
 	bool mapBuffers = (gl_extensions.bugs & BUG_ANY_MAP_BUFFER_RANGE_SLOW) == 0;
 	bool hasBufferStorage = gl_extensions.ARB_buffer_storage || gl_extensions.EXT_buffer_storage;
@@ -574,7 +580,7 @@ GLPushBuffer::GLPushBuffer(GLRenderManager *render, GLuint target, size_t size)
 }
 
 GLPushBuffer::~GLPushBuffer() {
-	Destroy();
+	Destroy(true);
 }
 
 void GLPushBuffer::Map() {
@@ -606,6 +612,8 @@ void GLPushBuffer::Unmap() {
 
 void GLPushBuffer::Flush() {
 	// Must be called from the render thread.
+	_dbg_assert_(G3D, OnRenderThread());
+
 	buffers_[buf_].flushOffset = offset_;
 	if (!buffers_[buf_].deviceMemory && writePtr_) {
 		auto &info = buffers_[buf_];
@@ -647,12 +655,18 @@ bool GLPushBuffer::AddBuffer() {
 }
 
 // Executed on the render thread!
-void GLPushBuffer::Destroy() {
+void GLPushBuffer::Destroy(bool onRenderThread) {
 	for (BufInfo &info : buffers_) {
 		// This will automatically unmap device memory, if needed.
-		// NOTE: We immediately delete the buffer, don't go through the deleter, since we're on the render thread.
-		// render_->DeleteBuffer(info.buffer);
-		delete info.buffer;
+		// NOTE: We immediately delete the buffer, don't go through the deleter, if we're on the render thread.
+		if (onRenderThread) {
+			_dbg_assert_(G3D, OnRenderThread());
+			delete info.buffer;
+		} else {
+			_dbg_assert_(G3D, !OnRenderThread());
+			render_->DeleteBuffer(info.buffer);
+		}
+
 		FreeAlignedMemory(info.localMemory);
 	}
 	buffers_.clear();
@@ -684,6 +698,8 @@ void GLPushBuffer::NextBuffer(size_t minSize) {
 }
 
 void GLPushBuffer::Defragment() {
+	_dbg_assert_(G3D, std::this_thread::get_id() != renderThreadId);
+
 	if (buffers_.size() <= 1) {
 		// Let's take this chance to jetison localMemory we don't need.
 		for (auto &info : buffers_) {
@@ -698,7 +714,7 @@ void GLPushBuffer::Defragment() {
 
 	// Okay, we have more than one.  Destroy them all and start over with a larger one.
 	size_t newSize = size_ * buffers_.size();
-	Destroy();
+	Destroy(false);
 
 	size_ = newSize;
 	bool res = AddBuffer();
@@ -714,6 +730,8 @@ size_t GLPushBuffer::GetTotalSize() const {
 }
 
 void GLPushBuffer::MapDevice(GLBufferStrategy strategy) {
+	_dbg_assert_(G3D, OnRenderThread());
+
 	strategy_ = strategy;
 	if (strategy_ == GLBufferStrategy::SUBDATA) {
 		return;
@@ -746,6 +764,8 @@ void GLPushBuffer::MapDevice(GLBufferStrategy strategy) {
 }
 
 void GLPushBuffer::UnmapDevice() {
+	_dbg_assert_(G3D, OnRenderThread());
+
 	for (auto &info : buffers_) {
 		if (info.deviceMemory) {
 			// TODO: Technically this can return false?
diff --git a/ext/native/thin3d/GLRenderManager.h b/ext/native/thin3d/GLRenderManager.h
index b54697b432..d241812441 100644
--- a/ext/native/thin3d/GLRenderManager.h
+++ b/ext/native/thin3d/GLRenderManager.h
@@ -288,7 +288,7 @@ private:
 	bool AddBuffer();
 	void NextBuffer(size_t minSize);
 	void Defragment();
-	void Destroy();
+	void Destroy(bool onRenderThread);
 
 	GLRenderManager *render_;
 	std::vector<BufInfo> buffers_;