diff --git a/Common/Data/Format/JSONReader.cpp b/Common/Data/Format/JSONReader.cpp
index 7fbe1ab2d2..6e7af3634f 100644
--- a/Common/Data/Format/JSONReader.cpp
+++ b/Common/Data/Format/JSONReader.cpp
@@ -36,7 +36,7 @@ bool JsonReader::parse() {
 int JsonGet::numChildren() const {
 	int count = 0;
 	if (value_.getTag() == JSON_OBJECT || value_.getTag() == JSON_ARRAY) {
-		for (auto it : value_) {
+		for (const auto &it : value_) {
 			(void)it;
 			count++;
 		}
@@ -52,7 +52,7 @@ const JsonNode *JsonGet::get(const char *child_name) const {
 	if (value_.getTag() != JSON_OBJECT) {
 		return nullptr;
 	}
-	for (auto it : value_) {
+	for (const auto &it : value_) {
 		if (!strcmp(it->key, child_name)) {
 			return it;
 		}
@@ -94,7 +94,7 @@ const char *JsonGet::getStringOr(const char *child_name, const char *default_val
 bool JsonGet::getStringVector(std::vector<std::string> *vec) const {
 	vec->clear();
 	if (value_.getTag() == JSON_ARRAY) {
-		for (auto it : value_) {
+		for (const auto &it : value_) {
 			if (it->value.getTag() == JSON_STRING) {
 				vec->push_back(it->value.toString());
 			}
diff --git a/Common/GPU/OpenGL/GLQueueRunner.cpp b/Common/GPU/OpenGL/GLQueueRunner.cpp
index 323976d9ad..803e22d2f1 100644
--- a/Common/GPU/OpenGL/GLQueueRunner.cpp
+++ b/Common/GPU/OpenGL/GLQueueRunner.cpp
@@ -198,7 +198,7 @@ void GLQueueRunner::RunInitSteps(const FastVec<GLRInitStep> &steps, bool skipGLC
 				glAttachShader(program->program, step.create_program.shaders[j]->shader);
 			}
 
-			for (auto iter : program->semantics_) {
+			for (const auto &iter : program->semantics_) {
 				glBindAttribLocation(program->program, iter.location, iter.attrib);
 			}
 
@@ -304,7 +304,7 @@ void GLQueueRunner::RunInitSteps(const FastVec<GLRInitStep> &steps, bool skipGLC
 					LineNumberString(code).c_str());
 				std::vector<std::string_view> lines;
 				SplitString(errorString, '\n', lines);
-				for (auto line : lines) {
+				for (const auto &line : lines) {
 					ERROR_LOG(Log::G3D, "%.*s", (int)line.size(), line.data());
 				}
 				if (errorCallback_) {
diff --git a/Common/GPU/Vulkan/VulkanRenderManager.cpp b/Common/GPU/Vulkan/VulkanRenderManager.cpp
index 4f16a81b2f..5a117a6db3 100644
--- a/Common/GPU/Vulkan/VulkanRenderManager.cpp
+++ b/Common/GPU/Vulkan/VulkanRenderManager.cpp
@@ -507,7 +507,7 @@ void VulkanRenderManager::CompileThreadFunc() {
 			}
 		}
 
-		for (auto iter : map) {
+		for (const auto &iter : map) {
 			auto &shaders = iter.first;
 			auto &entries = iter.second;
 
diff --git a/Common/GPU/thin3d.cpp b/Common/GPU/thin3d.cpp
index 72fbe873e8..485fed453a 100644
--- a/Common/GPU/thin3d.cpp
+++ b/Common/GPU/thin3d.cpp
@@ -528,7 +528,7 @@ const UniformBufferDesc vsTexColBufDesc{ sizeof(VsTexColUB),{
 
 ShaderModule *CreateShader(DrawContext *draw, ShaderStage stage, const std::vector<ShaderSource> &sources) {
 	uint32_t supported = draw->GetSupportedShaderLanguages();
-	for (auto iter : sources) {
+	for (const auto &iter : sources) {
 		if ((uint32_t)iter.lang & supported) {
 			return draw->CreateShaderModule(stage, iter.lang, (const uint8_t *)iter.src, strlen(iter.src));
 		}
diff --git a/Common/Net/HTTPRequest.cpp b/Common/Net/HTTPRequest.cpp
index 3be4e8281c..b5b8a5c425 100644
--- a/Common/Net/HTTPRequest.cpp
+++ b/Common/Net/HTTPRequest.cpp
@@ -160,7 +160,7 @@ std::shared_ptr<Request> RequestManager::AsyncPostWithCallback(
 }
 
 void RequestManager::Update() {
-	for (auto iter : newDownloads_) {
+	for (auto &iter : newDownloads_) {
 		downloads_.push_back(iter);
 	}
 	newDownloads_.clear();
diff --git a/Core/FileLoaders/CachingFileLoader.cpp b/Core/FileLoaders/CachingFileLoader.cpp
index 5a419502e6..d787c97576 100644
--- a/Core/FileLoaders/CachingFileLoader.cpp
+++ b/Core/FileLoaders/CachingFileLoader.cpp
@@ -116,7 +116,7 @@ void CachingFileLoader::ShutdownCache() {
 		aheadThread_.join();
 
 	std::lock_guard<std::recursive_mutex> guard(blocksMutex_);
-	for (auto block : blocks_) {
+	for (const auto &block : blocks_) {
 		delete [] block.second.ptr;
 	}
 	blocks_.clear();
diff --git a/Core/FileLoaders/DiskCachingFileLoader.cpp b/Core/FileLoaders/DiskCachingFileLoader.cpp
index 12b715072c..6a36add50d 100644
--- a/Core/FileLoaders/DiskCachingFileLoader.cpp
+++ b/Core/FileLoaders/DiskCachingFileLoader.cpp
@@ -129,7 +129,7 @@ std::vector<Path> DiskCachingFileLoader::GetCachedPathsInUse() {
 	std::vector<Path> files;
 	files.reserve(caches_.size());
 
-	for (auto it : caches_) {
+	for (const auto &it : caches_) {
 		files.push_back(it.first);
 	}
 
diff --git a/Core/FileSystems/MetaFileSystem.cpp b/Core/FileSystems/MetaFileSystem.cpp
index 910b1b7f8a..bc9464274a 100644
--- a/Core/FileSystems/MetaFileSystem.cpp
+++ b/Core/FileSystems/MetaFileSystem.cpp
@@ -646,7 +646,7 @@ void MetaFileSystem::DoState(PointerWrap &p) {
 int64_t MetaFileSystem::RecursiveSize(const std::string &dirPath) {
 	u64 result = 0;
 	auto allFiles = GetDirListing(dirPath);
-	for (auto file : allFiles) {
+	for (const auto &file : allFiles) {
 		if (file.name == "." || file.name == "..")
 			continue;
 		if (file.type == FILETYPE_DIRECTORY) {
diff --git a/Core/HLE/sceFont.cpp b/Core/HLE/sceFont.cpp
index 2a06454f79..2856a5232a 100644
--- a/Core/HLE/sceFont.cpp
+++ b/Core/HLE/sceFont.cpp
@@ -742,7 +742,7 @@ public:
 private:
 	int FindExistingIndex(Font *font) const {
 		// TODO: Should this also match for memory fonts, or only internal fonts?
-		for (auto it : fontMap) {
+		for (const auto &it : fontMap) {
 			if (it.second->GetFont() != font || it.second->GetFontLib() != this)
 				continue;
 			for (size_t i = 0; i < fonts_.size(); i++) {
diff --git a/Core/HLE/sceHeap.cpp b/Core/HLE/sceHeap.cpp
index 49e17da3b0..bd880f3b9d 100644
--- a/Core/HLE/sceHeap.cpp
+++ b/Core/HLE/sceHeap.cpp
@@ -75,7 +75,7 @@ void __HeapInit() {
 }
 
 void __HeapShutdown() {
-	for (auto it : heapList) {
+	for (const auto &it : heapList) {
 		delete it.second;
 	}
 	heapList.clear();
diff --git a/Core/HLE/sceKernelModule.cpp b/Core/HLE/sceKernelModule.cpp
index f7f2954088..03ed76b41d 100644
--- a/Core/HLE/sceKernelModule.cpp
+++ b/Core/HLE/sceKernelModule.cpp
@@ -542,7 +542,7 @@ static void WriteVarSymbol(WriteVarSymbolState &state, u32 exportAddress, u32 re
 				ERROR_LOG_REPORT(Log::Loader, "HI16 and LO16 imports do not match at %08x for %08x (should be %08x)", relocAddress, state.lastHI16ExportAddress, exportAddress);
 			} else {
 				// Process each of the HI16.  Usually there's only one.
-				for (auto &reloc : state.lastHI16Relocs) {
+				for (const auto &reloc : state.lastHI16Relocs) {
 					if (!reverse) {
 						full = (reloc.data << 16) + offsetLo + exportAddress;
 					} else {
diff --git a/Core/HLE/sceNet.cpp b/Core/HLE/sceNet.cpp
index 5c663066e1..a3c739d6b5 100644
--- a/Core/HLE/sceNet.cpp
+++ b/Core/HLE/sceNet.cpp
@@ -119,7 +119,7 @@ std::string InfraDNSConfig::ToString() const {
 	}
 	if (!fixedDNS.empty()) {
 		w.C("Fixed DNS").endl();
-		for (auto iter : fixedDNS) {
+		for (const auto &iter : fixedDNS) {
 			w.F("%s -> %s", iter.first.c_str(), iter.second.c_str()).endl();
 		}
 	}
@@ -290,7 +290,7 @@ bool LoadDNSForGameID(std::string_view gameID, std::string_view jsonStr, InfraDN
 		dns->connectAdHocForGrouping = game.getBool("connect_adhoc_for_grouping", dns->connectAdHocForGrouping);
 		if (game.hasChild("domains", JSON_OBJECT)) {
 			const JsonGet domains = game.getDict("domains");
-			for (auto iter : domains.value_) {
+			for (const auto &iter : domains.value_) {
 				std::string domain = std::string(iter->key);
 				std::string ipAddr = std::string(iter->value.toString());
 				dns->fixedDNS[domain] = ipAddr;
diff --git a/Core/HLE/scePsmf.cpp b/Core/HLE/scePsmf.cpp
index 40b92f2d4b..e8ff6905cd 100644
--- a/Core/HLE/scePsmf.cpp
+++ b/Core/HLE/scePsmf.cpp
@@ -594,7 +594,7 @@ bool Psmf::setStreamNum(u32 psmfStruct, int num, bool updateCached) {
 }
 
 bool Psmf::setStreamWithType(u32 psmfStruct, int type, int channel) {
-	for (auto iter : streamMap) {
+	for (const auto &iter : streamMap) {
 		// Note: this does NOT support PSMF_AUDIO_STREAM.
 		if (iter.second->type_ == type && iter.second->channel_ == channel) {
 			return setStreamNum(psmfStruct, iter.first);
@@ -604,7 +604,7 @@ bool Psmf::setStreamWithType(u32 psmfStruct, int type, int channel) {
 }
 
 bool Psmf::setStreamWithTypeNumber(u32 psmfStruct, int type, int n) {
-	for (auto iter : streamMap) {
+	for (const auto &iter : streamMap) {
 		if (iter.second->matchesType(type)) {
 			if (n != 0) {
 				// Keep counting...
@@ -797,7 +797,7 @@ static u32 scePsmfGetNumberOfSpecificStreams(u32 psmfStruct, int streamType) {
 	}
 
 	int streamNum = 0;
-	for (auto it : psmf->streamMap) {
+	for (const auto &it : psmf->streamMap) {
 		if (it.second->matchesType(streamType)) {
 			streamNum++;
 		}
diff --git a/Core/HW/MediaEngine.cpp b/Core/HW/MediaEngine.cpp
index 59013aa7cb..96b54e5ab2 100644
--- a/Core/HW/MediaEngine.cpp
+++ b/Core/HW/MediaEngine.cpp
@@ -356,7 +356,7 @@ void MediaEngine::closeContext()
 		av_free(m_pIOContext->buffer);
 	if (m_pIOContext)
 		av_free(m_pIOContext);
-	for (auto it : m_pCodecCtxs) {
+	for (const auto &it : m_pCodecCtxs) {
 #if LIBAVFORMAT_VERSION_INT >= AV_VERSION_INT(57, 33, 100)
 		avcodec_free_context(&it.second);
 #else
@@ -365,7 +365,7 @@ void MediaEngine::closeContext()
 	}
 	m_pCodecCtxs.clear();
 	// These are streams allocated from avformat_new_stream.
-	for (auto it : m_codecsToClose) {
+	for (const auto &it : m_codecsToClose) {
 		avcodec_close(it);
 	}
 	m_codecsToClose.clear();
diff --git a/Core/MIPS/x86/X64IRAsm.cpp b/Core/MIPS/x86/X64IRAsm.cpp
index 883149dcd5..5cf4136930 100644
--- a/Core/MIPS/x86/X64IRAsm.cpp
+++ b/Core/MIPS/x86/X64IRAsm.cpp
@@ -303,7 +303,7 @@ void X64JitBackend::GenerateFixedCode(MIPSState *mipsState) {
 	if (enableDisasm) {
 #if PPSSPP_ARCH(AMD64)
 		std::vector<std::string> lines = DisassembleX86(disasmStart, (int)(GetCodePtr() - disasmStart));
-		for (auto s : lines) {
+		for (const auto &s : lines) {
 			INFO_LOG(Log::JIT, "%s", s.c_str());
 		}
 #endif
diff --git a/Core/System.cpp b/Core/System.cpp
index 6a8f3ab1f0..fd976a4b23 100644
--- a/Core/System.cpp
+++ b/Core/System.cpp
@@ -589,7 +589,7 @@ BootState PSP_InitUpdate(std::string *error_string) {
 	_dbg_assert_(g_bootState == BootState::Complete || g_bootState == BootState::Failed);
 
 	// Since we load on a background thread, wait for startup to complete.
-	_dbg_assert_(g_loadingThread.joinable());
+	_assert_msg_(g_loadingThread.joinable(), "bootstate: %d", (int)g_bootState);
 	g_loadingThread.join();
 
 	if (g_bootState == BootState::Failed) {
diff --git a/UI/EmuScreen.cpp b/UI/EmuScreen.cpp
index 9066920672..fa00cb48a7 100644
--- a/UI/EmuScreen.cpp
+++ b/UI/EmuScreen.cpp
@@ -345,8 +345,10 @@ void EmuScreen::ProcessGameBoot(const Path &filename) {
 		return;
 	}
 
-	loadingViewColor_->Divert(0xFFFFFFFF, 0.75f);
-	loadingViewVisible_->Divert(UI::V_VISIBLE, 0.75f);
+	if (loadingViewColor_)
+		loadingViewColor_->Divert(0xFFFFFFFF, 0.75f);
+	if (loadingViewVisible_)
+		loadingViewVisible_->Divert(UI::V_VISIBLE, 0.75f);
 
 	screenManager()->getDrawContext()->ResetStats();
 
@@ -431,8 +433,10 @@ void EmuScreen::bootComplete() {
 
 	saveStateSlot_ = SaveState::GetCurrentSlot();
 
-	loadingViewColor_->Divert(0x00FFFFFF, 0.2f);
-	loadingViewVisible_->Divert(UI::V_INVISIBLE, 0.2f);
+	if (loadingViewColor_)
+		loadingViewColor_->Divert(0x00FFFFFF, 0.2f);
+	if (loadingViewVisible_)
+		loadingViewVisible_->Divert(UI::V_INVISIBLE, 0.2f);
 
 	std::string gameID = g_paramSFO.GetValueString("DISC_ID");
 	g_Config.TimeTracker().Start(gameID);