diff --git a/Core/HLE/AtracCtx.h b/Core/HLE/AtracCtx.h
index 8f2bf38fda..0212aa0884 100644
--- a/Core/HLE/AtracCtx.h
+++ b/Core/HLE/AtracCtx.h
@@ -291,6 +291,7 @@ public:
 	}
 
 	u8 *BufferStart();
+
 	void DoState(PointerWrap &p) override;
 	void WriteContextToPSPMem() override;
 
diff --git a/Core/HLE/HLE.cpp b/Core/HLE/HLE.cpp
index 6fbe816b45..cdc8a8d7ba 100644
--- a/Core/HLE/HLE.cpp
+++ b/Core/HLE/HLE.cpp
@@ -162,14 +162,20 @@ void HLEShutdown() {
 	mipsCallActions.clear();
 }
 
-void RegisterModule(const char *name, int numFunctions, const HLEFunction *funcTable)
-{
+int GetNumRegisteredModules() {
+	return (int)moduleDB.size();
+}
+
+void RegisterModule(const char *name, int numFunctions, const HLEFunction *funcTable) {
 	HLEModule module = {name, numFunctions, funcTable};
 	moduleDB.push_back(module);
 }
 
-int GetModuleIndex(const char *moduleName)
-{
+const HLEModule *GetModuleByIndex(int index) {
+	return &moduleDB[index];
+}
+
+int GetModuleIndex(const char *moduleName) {
 	for (size_t i = 0; i < moduleDB.size(); i++)
 		if (strcmp(moduleName, moduleDB[i].name) == 0)
 			return (int)i;
diff --git a/Core/HLE/HLE.h b/Core/HLE/HLE.h
index ba96ef4570..12a0590351 100644
--- a/Core/HLE/HLE.h
+++ b/Core/HLE/HLE.h
@@ -44,8 +44,7 @@ enum {
 	HLE_KERNEL_SYSCALL = 1 << 11,
 };
 
-struct HLEFunction
-{
+struct HLEFunction {
 	// This is the id, or nid, of the function (which is how it's linked.)
 	// Generally, the truncated least significant 32 bits of a SHA-1 hash.
 	u32 ID;
@@ -72,8 +71,7 @@ struct HLEFunction
 	u32 stackBytesToClear;
 };
 
-struct HLEModule
-{
+struct HLEModule {
 	const char *name;
 	int numFunctions;
 	const HLEFunction *funcTable;
@@ -81,8 +79,7 @@ struct HLEModule
 
 typedef char SyscallModuleName[32];
 
-struct Syscall
-{
+struct Syscall {
 	SyscallModuleName moduleName;
 	u32 symAddr;
 	u32 nid;
@@ -102,6 +99,8 @@ int GetFuncIndex(int moduleIndex, u32 nib);
 int GetModuleIndex(const char *modulename);
 
 void RegisterModule(const char *name, int numFunctions, const HLEFunction *funcTable);
+int GetNumRegisteredModules();
+const HLEModule *GetModuleByIndex(int index);
 
 // Run the current thread's callbacks after the syscall finishes.
 void hleCheckCurrentCallbacks();
diff --git a/Core/HLE/sceAtrac.cpp b/Core/HLE/sceAtrac.cpp
index 9f74b329a9..f4d99f6313 100644
--- a/Core/HLE/sceAtrac.cpp
+++ b/Core/HLE/sceAtrac.cpp
@@ -75,13 +75,20 @@
 
 static const int atracDecodeDelay = 2300;
 
-const int PSP_NUM_ATRAC_IDS = 6;
 static bool atracInited = true;
 static AtracBase *atracContexts[PSP_NUM_ATRAC_IDS];
 static u32 atracContextTypes[PSP_NUM_ATRAC_IDS];
 static int atracLibVersion = 0;
 static u32 atracLibCrc = 0;
 
+// For debugger only.
+const AtracBase *__AtracGetCtx(int i, u32 *type) {
+	if (type) {
+		*type = atracContextTypes[i];
+	}
+	return atracContexts[i];
+}
+
 void __AtracInit() {
 	_assert_(sizeof(SceAtracContext) == 256);
 
diff --git a/Core/HLE/sceAtrac.h b/Core/HLE/sceAtrac.h
index f29c59f798..e0bf3ec86c 100644
--- a/Core/HLE/sceAtrac.h
+++ b/Core/HLE/sceAtrac.h
@@ -85,6 +85,12 @@ struct SceAtracContext {
     SceAtracIdInfo info;
 };
 
+const int PSP_NUM_ATRAC_IDS = 6;
+
+class AtracBase;
+
+const AtracBase *__AtracGetCtx(int i, u32 *type);
+
 // External interface used by sceSas.
 u32 AtracSasAddStreamData(int atracID, u32 bufPtr, u32 bytesToAdd);
 u32 AtracSasDecodeData(int atracID, u8* outbuf, u32 outbufPtr, u32 *SamplesNum, u32* finish, int *remains);
diff --git a/Core/MIPS/MIPSStackWalk.cpp b/Core/MIPS/MIPSStackWalk.cpp
index 60e38a0658..446c31d6c9 100644
--- a/Core/MIPS/MIPSStackWalk.cpp
+++ b/Core/MIPS/MIPSStackWalk.cpp
@@ -15,6 +15,7 @@
 // Official git repository and contact information can be found at
 // https://github.com/hrydgard/ppsspp and http://www.ppsspp.org/.
 
+#include "Common/Log.h"
 #include "Core/MemMap.h"
 #include "Core/Debugger/SymbolMap.h"
 #include "Core/MIPS/MIPSCodeUtils.h"
@@ -112,6 +113,7 @@ namespace MIPSStackWalk {
 			stop = start - LONGEST_FUNCTION;
 		}
 		for (u32 pc = start; Memory::IsValidAddress(pc) && pc >= stop; pc -= 4) {
+			_dbg_assert_(Memory::IsValidAddress(pc));
 			MIPSOpcode op = Memory::Read_Instruction(pc, true);
 
 			// Here's where they store the ra address.
@@ -161,7 +163,7 @@ namespace MIPSStackWalk {
 		}
 	}
 
-	std::vector<StackFrame> Walk(u32 pc, u32 ra, u32 sp, u32 threadEntry, u32 threadStackTop) {
+	std::vector<StackFrame> Walk(const u32 pc, u32 ra, u32 sp, const u32 threadEntry, u32 threadStackTop) {
 		std::vector<StackFrame> frames;
 
 		if (!Memory::IsValidAddress(pc) || !Memory::IsValidAddress(sp) || !Memory::IsValidAddress(ra)) {
@@ -175,7 +177,11 @@ namespace MIPSStackWalk {
 		current.stackSize = -1;
 
 		u32 prevEntry = INVALIDTARGET;
-		while (pc != threadEntry) {
+		while (current.pc != threadEntry) {
+			if (!Memory::IsValidAddress(current.pc)) {
+				break;
+			}
+
 			u32 possibleEntry = GuessEntry(current.pc);
 			if (DetermineFrameInfo(current, possibleEntry, threadEntry, ra)) {
 				frames.push_back(current);
diff --git a/Core/MemMap.cpp b/Core/MemMap.cpp
index 67bbe6f9f3..26182005f5 100644
--- a/Core/MemMap.cpp
+++ b/Core/MemMap.cpp
@@ -158,8 +158,8 @@ static bool Memory_TryBase(u32 flags) {
 		*view.out_ptr = (u8*)g_arena.CreateView(
 			position, view.size, base + view.virtual_address);
 		if (!*view.out_ptr) {
+			ERROR_LOG(Log::MemMap, "Failed at view %d", i);
 			goto bail;
-			DEBUG_LOG(Log::MemMap, "Failed at view %d", i);
 		}
 #else
 		if (CanIgnoreView(view)) {
@@ -169,7 +169,7 @@ static bool Memory_TryBase(u32 flags) {
 			*view.out_ptr = (u8*)g_arena.CreateView(
 				position, view.size, base + (view.virtual_address & MEMVIEW32_MASK));
 			if (!*view.out_ptr) {
-				DEBUG_LOG(Log::MemMap, "Failed at view %d", i);
+				ERROR_LOG(Log::MemMap, "Failed at view %d", i);
 				goto bail;
 			}
 		}
@@ -185,11 +185,11 @@ bail:
 		if (views[i].size == 0)
 			continue;
 		SKIP(flags, views[i].flags);
-		if (*views[j].out_ptr) {
+		if (views[j].out_ptr && *views[j].out_ptr) {
 			if (!CanIgnoreView(views[j])) {
 				g_arena.ReleaseView(0, *views[j].out_ptr, views[j].size);
 			}
-			*views[j].out_ptr = NULL;
+			*views[j].out_ptr = nullptr;
 		}
 	}
 	return false;
diff --git a/UI/ImDebugger/ImDebugger.cpp b/UI/ImDebugger/ImDebugger.cpp
index b9a3273499..aa15f8fec6 100644
--- a/UI/ImDebugger/ImDebugger.cpp
+++ b/UI/ImDebugger/ImDebugger.cpp
@@ -1,3 +1,5 @@
+#include <algorithm>
+
 
 #include "ext/imgui/imgui_internal.h"
 
@@ -11,8 +13,12 @@
 #include "Core/MIPS/MIPSTables.h"
 #include "Core/Debugger/SymbolMap.h"
 #include "Core/MemMap.h"
+#include "Core/HLE/HLE.h"
 #include "Common/System/Request.h"
 
+#include "Core/HLE/sceAtrac.h"
+#include "Core/HLE/AtracCtx.h"
+
 // Threads window
 #include "Core/HLE/sceKernelThread.h"
 
@@ -104,8 +110,8 @@ static const char *ThreadStatusToString(u32 status) {
 	return "(unk)";
 }
 
-void DrawThreadView(bool *open) {
-	if (!ImGui::Begin("Threads", open)) {
+void DrawThreadView(ImConfig &cfg) {
+	if (!ImGui::Begin("Threads", &cfg.threadsOpen)) {
 		ImGui::End();
 		return;
 	}
@@ -119,22 +125,78 @@ void DrawThreadView(bool *open) {
 		ImGui::TableSetupColumn("State", ImGuiTableColumnFlags_WidthStretch);
 
 		ImGui::TableHeadersRow();
-		ImGui::TableNextRow();
 
-		// TODO: Add context menu
-		for (auto &thread : info) {
-			ImGui::TableSetColumnIndex(0);
-			ImGui::Text("%s", thread.name);
-			ImGui::TableSetColumnIndex(1);
-			ImGui::Text("%08x", thread.curPC);
-			ImGui::TableSetColumnIndex(2);
-			ImGui::Text("%08x", thread.entrypoint);
-			ImGui::TableSetColumnIndex(3);
-			ImGui::Text("%d", thread.priority);
-			ImGui::TableSetColumnIndex(4);
-			ImGui::Text("%s", ThreadStatusToString(thread.status));
+		for (int i = 0; i < (int)info.size(); i++) {
+			const auto &thread = info[i];
 			ImGui::TableNextRow();
-			// TODO: More fields?
+			ImGui::TableNextColumn();
+			ImGui::PushID(i);
+			if (ImGui::Selectable(thread.name, cfg.selectedThread == i, ImGuiSelectableFlags_AllowDoubleClick | ImGuiSelectableFlags_SpanAllColumns)) {
+				cfg.selectedThread = i;
+			}
+			if (ImGui::IsItemClicked(ImGuiMouseButton_Right)) {
+				cfg.selectedThread = i;
+				ImGui::OpenPopup("threadPopup");
+			}
+			ImGui::TableNextColumn();
+			ImGui::Text("%08x", thread.curPC);
+			ImGui::TableNextColumn();
+			ImGui::Text("%08x", thread.entrypoint);
+			ImGui::TableNextColumn();
+			ImGui::Text("%d", thread.priority);
+			ImGui::TableNextColumn();
+			ImGui::Text("%s", ThreadStatusToString(thread.status));
+			if (ImGui::BeginPopup("threadPopup")) {
+				DebugThreadInfo &thread = info[i];
+				ImGui::Text("Thread: %s", thread.name);
+				if (ImGui::MenuItem("Kill thread")) {
+					sceKernelTerminateThread(thread.id);
+				}
+				if (ImGui::MenuItem("Force run")) {
+					__KernelResumeThreadFromWait(thread.id, 0);
+				}
+				ImGui::EndPopup();
+			}
+			ImGui::PopID();
+		}
+
+		ImGui::EndTable();
+	}
+	ImGui::End();
+}
+
+void DrawAtracView(ImConfig &cfg) {
+	if (!ImGui::Begin("sceAtrac contexts", &cfg.atracOpen)) {
+		ImGui::End();
+		return;
+	}
+
+	if (ImGui::BeginTable("atracs", 5, ImGuiTableFlags_RowBg | ImGuiTableFlags_BordersH)) {
+		ImGui::TableSetupColumn("Type", ImGuiTableColumnFlags_WidthFixed);
+		ImGui::TableSetupColumn("OutChans", ImGuiTableColumnFlags_WidthFixed);
+		ImGui::TableSetupColumn("CurrentSample", ImGuiTableColumnFlags_WidthFixed);
+		ImGui::TableSetupColumn("RemainingFrames", ImGuiTableColumnFlags_WidthFixed);
+
+		ImGui::TableHeadersRow();
+
+		for (int i = 0; i < PSP_NUM_ATRAC_IDS; i++) {
+			u32 type = 0;
+			const AtracBase *atracBase = __AtracGetCtx(i, &type);
+			ImGui::TableNextRow();
+			ImGui::TableNextColumn();
+
+			if (!atracBase) {
+				ImGui::Text("-", type);
+				continue;
+			}
+
+			ImGui::Text("%d", type);
+			ImGui::TableNextColumn();
+			ImGui::Text("%d", atracBase->GetOutputChannels());
+			ImGui::TableNextColumn();
+			ImGui::Text("%d", atracBase->CurrentSample());
+			ImGui::TableNextColumn();
+			ImGui::Text("%d", atracBase->RemainingFrames());
 		}
 
 		ImGui::EndTable();
@@ -198,14 +260,13 @@ void DrawCallStacks(MIPSDebugInterface *debug, bool *open) {
 	ImGui::End();
 }
 
-void DrawModules(MIPSDebugInterface *debug, bool *open) {
-	if (!ImGui::Begin("Modules", open) || !g_symbolMap) {
+void DrawModules(MIPSDebugInterface *debug, ImConfig &cfg) {
+	if (!ImGui::Begin("Modules", &cfg.modulesOpen) || !g_symbolMap) {
 		ImGui::End();
 		return;
 	}
 
 	std::vector<LoadedModuleInfo> modules = g_symbolMap->getAllModules();
-
 	if (ImGui::BeginTable("modules", 4, ImGuiTableFlags_RowBg | ImGuiTableFlags_BordersH)) {
 		ImGui::TableSetupColumn("Name", ImGuiTableColumnFlags_WidthFixed);
 		ImGui::TableSetupColumn("Address", ImGuiTableColumnFlags_WidthFixed);
@@ -213,23 +274,60 @@ void DrawModules(MIPSDebugInterface *debug, bool *open) {
 		ImGui::TableSetupColumn("Active", ImGuiTableColumnFlags_WidthFixed);
 
 		ImGui::TableHeadersRow();
-		ImGui::TableNextRow();
 
 		// TODO: Add context menu and clickability
-		for (auto &module : modules) {
-			ImGui::TableSetColumnIndex(0);
-			ImGui::Text("%s", module.name.c_str());
-			ImGui::TableSetColumnIndex(1);
-			ImGui::Text("%08x", module.address);
-			ImGui::TableSetColumnIndex(2);
-			ImGui::Text("%08x", module.size);
-			ImGui::TableSetColumnIndex(3);
-			ImGui::Text("%s", module.active ? "yes" : "no");
+		for (int i = 0; i < (int)modules.size(); i++) {
+			auto &module = modules[i];
 			ImGui::TableNextRow();
+			ImGui::TableNextColumn();
+			if (ImGui::Selectable(module.name.c_str(), cfg.selectedModule == i, ImGuiSelectableFlags_SpanAllColumns)) {
+				cfg.selectedModule = i;
+			}
+			ImGui::TableNextColumn();
+			ImGui::Text("%08x", module.address);
+			ImGui::TableNextColumn();
+			ImGui::Text("%08x", module.size);
+			ImGui::TableNextColumn();
+			ImGui::Text("%s", module.active ? "yes" : "no");
 		}
 
 		ImGui::EndTable();
 	}
+
+	if (cfg.selectedModule >= 0 && cfg.selectedModule < (int)modules.size()) {
+		auto &module = modules[cfg.selectedModule];
+		// TODO: Show details
+	}
+	ImGui::End();
+}
+
+void DrawHLEModules(ImConfig &config) {
+	if (!ImGui::Begin("HLE Modules", &config.hleModulesOpen)) {
+		ImGui::End();
+		return;
+	}
+
+	const int moduleCount = GetNumRegisteredModules();
+	std::vector<const HLEModule *> modules;
+	modules.reserve(moduleCount);
+	for (int i = 0; i < moduleCount; i++) {
+		modules.push_back(GetModuleByIndex(i));
+	}
+
+	std::sort(modules.begin(), modules.end(), [](const HLEModule* a, const HLEModule* b) {
+		return std::strcmp(a->name, b->name) < 0;
+	});
+
+	for (auto mod : modules) {
+		if (ImGui::TreeNode(mod->name)) {
+			for (int j = 0; j < mod->numFunctions; j++) {
+				auto &func = mod->funcTable[j];
+				ImGui::Text("%s(%s)", func.name, func.argmask);
+			}
+			ImGui::TreePop();
+		}
+	}
+
 	ImGui::End();
 }
 
@@ -272,40 +370,47 @@ void ImDebugger::Frame(MIPSDebugInterface *mipsDebug) {
 			ImGui::EndMenu();
 		}
 		if (ImGui::BeginMenu("Window")) {
-			ImGui::Checkbox("Dear ImGUI Demo", &demoOpen_);
-			ImGui::Checkbox("CPU debugger", &disasmOpen_);
-			ImGui::Checkbox("Registers", &regsOpen_);
-			ImGui::Checkbox("Callstacks", &callstackOpen_);
-			ImGui::Checkbox("HLE Modules", &modulesOpen_);
-			ImGui::Checkbox("HLE Threads", &threadsOpen_);
+			ImGui::Checkbox("Dear ImGUI Demo", &cfg_.demoOpen);
+			ImGui::Checkbox("CPU debugger", &cfg_.disasmOpen);
+			ImGui::Checkbox("Registers", &cfg_.regsOpen);
+			ImGui::Checkbox("Callstacks", &cfg_.callstackOpen);
+			ImGui::Checkbox("HLE Modules", &cfg_.modulesOpen);
+			ImGui::Checkbox("HLE Threads", &cfg_.threadsOpen);
+			ImGui::Checkbox("sceAtrac", &cfg_.atracOpen);
 			ImGui::EndMenu();
 		}
 		ImGui::EndMainMenuBar();
 	}
 
-	if (demoOpen_) {
-		ImGui::ShowDemoWindow(&demoOpen_);
+	if (cfg_.demoOpen) {
+		ImGui::ShowDemoWindow(&cfg_.demoOpen);
 	}
 
-	if (disasmOpen_) {
-		disasm_.Draw(mipsDebug, &disasmOpen_, coreState);
+	if (cfg_.disasmOpen) {
+		disasm_.Draw(mipsDebug, &cfg_.disasmOpen, coreState);
 	}
 
-	if (regsOpen_) {
-		DrawRegisterView(mipsDebug, &regsOpen_);
+	if (cfg_.regsOpen) {
+		DrawRegisterView(mipsDebug, &cfg_.regsOpen);
 	}
 
-	if (threadsOpen_) {
-		DrawThreadView(&threadsOpen_);
+	if (cfg_.threadsOpen) {
+		DrawThreadView(cfg_);
 	}
 
-	if (callstackOpen_) {
-		DrawCallStacks(mipsDebug, &callstackOpen_);
+	if (cfg_.callstackOpen) {
+		DrawCallStacks(mipsDebug, &cfg_.callstackOpen);
 	}
 
-	if (modulesOpen_) {
-		DrawModules(mipsDebug, &modulesOpen_);
+	if (cfg_.modulesOpen) {
+		DrawModules(mipsDebug, cfg_);
 	}
+
+	if (cfg_.atracOpen) {
+		DrawAtracView(cfg_);
+	}
+
+	DrawHLEModules(cfg_);
 }
 
 void ImDisasmWindow::Draw(MIPSDebugInterface *mipsDebug, bool *open, CoreState coreState) {
diff --git a/UI/ImDebugger/ImDebugger.h b/UI/ImDebugger/ImDebugger.h
index 1eba71030c..389088deb6 100644
--- a/UI/ImDebugger/ImDebugger.h
+++ b/UI/ImDebugger/ImDebugger.h
@@ -48,6 +48,24 @@ public:
 	// Stub
 };
 
+struct ImConfig {
+	bool disasmOpen = true;
+	bool demoOpen  = false;
+	bool regsOpen = true;
+	bool threadsOpen = true;
+	bool callstackOpen = true;
+	bool modulesOpen = true;
+	bool hleModulesOpen = false;
+	bool atracOpen = true;
+
+	// HLE explorer settings
+	// bool filterByUsed = true;
+
+	// Various selections
+	int selectedModule = 0;
+	int selectedThread = 0;
+};
+
 struct ImDebugger {
 	void Frame(MIPSDebugInterface *mipsDebug);
 
@@ -55,10 +73,5 @@ struct ImDebugger {
 	ImLuaConsole luaConsole_;
 
 	// Open variables.
-	bool disasmOpen_ = true;
-	bool demoOpen_ = false;
-	bool regsOpen_ = true;
-	bool threadsOpen_ = true;
-	bool callstackOpen_ = true;
-	bool modulesOpen_ = true;
+	ImConfig cfg_;
 };