diff --git a/Core/System.cpp b/Core/System.cpp
index 0ea5f48330..6a14adb07c 100644
--- a/Core/System.cpp
+++ b/Core/System.cpp
@@ -512,8 +512,6 @@ bool PSP_InitStart(const CoreParameter &coreParam) {
 		return false;
 	}
 
-	_dbg_assert_(coreState != CORE_POWERUP);
-
 	coreState = CORE_POWERUP;
 
 	g_bootState = BootState::Booting;
@@ -616,6 +614,7 @@ BootState PSP_InitUpdate(std::string *error_string) {
 	if (!gpu) {  // should be!
 		INFO_LOG(Log::System, "Starting graphics...");
 		Draw::DrawContext *draw = g_CoreParameter.graphicsContext ? g_CoreParameter.graphicsContext->GetDrawContext() : nullptr;
+		// This set the `gpu` global.
 		bool success = GPU_Init(g_CoreParameter.graphicsContext, draw);
 		if (!success) {
 			*error_string = "Unable to initialize rendering engine.";
diff --git a/libretro/README_WINDOWS.txt b/libretro/README_WINDOWS.txt
index 61322ba004..4eb43f7d9d 100644
--- a/libretro/README_WINDOWS.txt
+++ b/libretro/README_WINDOWS.txt
@@ -8,13 +8,16 @@ You can probably really skip most of the packages but you need make:
 
 pacman -S make
 
-"Install" the plugin in Retroarch.
+Start Retroarch ones to create the cores directory.
 
 Then use the following in msys:
 
-cd libretro
+> cd libretro
+> make platform=windows_msvc2019_desktop_x64 -j32 && cp ppsspp_libretro.* /d/retroarch/cores
 
-make platform=windows_msvc2019_desktop_x64 -j32 && cp ppsspp_libretro.* /d/retroarch/cores
+To make a debug build:
+
+> make DEBUG=1 platform=windows_msvc2019_desktop_x64 -j32
 
 Note that the latter part copies the DLL/PDB into wherever retroarch reads it from. Might need to adjust the path,
 and adjust -j32 depending on your number of logical CPUs - might not need that many threads (or you might need more...).
@@ -23,8 +26,8 @@ Also, the "2019" part has no significance, it seems - it's fine even if you're o
 
 (plain make without a platform parameter doesn't work - g++ isn't able to build the D3D11 stuff, or at least it fails to link).
 
-To debug from within MSVC, open retroarch.exe (or retroarch_debug.exe) as a Project/Solution, then open a few of the cpp files,
-set some breakpoints and just launch using F5.
+To debug from within MSVC, open retroarch.exe (or retroarch_debug.exe) as a Project/Solution (important! Not as File), then open a few of the cpp files,
+set some breakpoints and just launch using F5. Then just choose the core and game in retroarch.
 
 Useful libretro/vulkan sample code:
 
diff --git a/libretro/libretro.cpp b/libretro/libretro.cpp
index 10f826b46e..d1fe05183d 100644
--- a/libretro/libretro.cpp
+++ b/libretro/libretro.cpp
@@ -104,6 +104,8 @@ namespace Libretro
    static retro_input_state_t input_state_cb;
    static retro_log_printf_t log_cb;
 
+   bool g_pendingBoot = false;
+
    static bool detectVsyncSwapInterval = false;
    static bool detectVsyncSwapIntervalOptShown = true;
    static bool softwareRenderInitHack = false;
@@ -1326,12 +1328,14 @@ namespace Libretro
       if (ctx->GetDrawContext())
          ctx->GetDrawContext()->BeginFrame(Draw::DebugFlags::NONE);
 
-      gpu->BeginHostFrame();
+      if (gpu)
+         gpu->BeginHostFrame();
 
       coreState = CORE_RUNNING_CPU;
       PSP_RunLoopWhileState();
 
-      gpu->EndHostFrame();
+      if (gpu)
+         gpu->EndHostFrame();
 
       if (ctx->GetDrawContext()) {
          ctx->GetDrawContext()->EndFrame();
@@ -1473,6 +1477,8 @@ bool retro_load_game(const struct retro_game_info *game)
    // set cpuCore from libretro setting variable
    coreParam.cpuCore         =  (CPUCore)g_Config.iCpuCore;
 
+   g_pendingBoot = true;
+
    std::string error_string;
    if (!PSP_InitStart(coreParam)) {
       // Can't really fail, the errors happen later during InitUpdate
@@ -1497,6 +1503,8 @@ bool retro_load_game(const struct retro_game_info *game)
 
    set_variable_visibility();
 
+   // NOTE: At this point we haven't really booted yet, but "in-game" we'll just keep polling
+   // PSP_InitUpdate until done.
    return true;
 }
 
@@ -1626,28 +1634,32 @@ static void retro_input(void)
 
 void retro_run(void)
 {
-   if (PSP_GetBootState() != BootState::Complete)
-   {
+   if (g_pendingBoot) {
       std::string error_string;
-      while (true) {
-         BootState state = PSP_InitUpdate(&error_string);
-         if (state == BootState::Failed) {
-            ERROR_LOG(Log::Boot, "%s", error_string.c_str());
-            environ_cb(RETRO_ENVIRONMENT_SHUTDOWN, nullptr);
-            return;
-         } else if (state == BootState::Complete) {
-            break;
-         }
-         sleep_ms(4, "libretro-init-poll");
+      BootState state = PSP_InitUpdate(&error_string);
+      if (state == BootState::Failed) {
+         g_pendingBoot = false;
+         ERROR_LOG(Log::Boot, "%s", error_string.c_str());
+         environ_cb(RETRO_ENVIRONMENT_SHUTDOWN, nullptr);
+         return;
+      } else if (state == BootState::Booting) {
+         // Not done yet. Do maintenance stuff and bail.
+         retro_input();
+         ctx->SwapBuffers();
+         return;
       }
 
-      if (softwareRenderInitHack)
-      {
-         log_cb(RETRO_LOG_DEBUG, "Software rendering init hack for opengl triggered.\n");
-         softwareRenderInitHack = false;
-         g_Config.bSoftwareRendering = true;
-         retro_reset();
-      }
+      // Here's where we finish the boot process.
+      g_pendingBoot = false;
+   }
+
+   // TODO: This seems dubious.
+   if (softwareRenderInitHack)
+   {
+      log_cb(RETRO_LOG_DEBUG, "Software rendering init hack for opengl triggered.\n");
+      softwareRenderInitHack = false;
+      g_Config.bSoftwareRendering = true;
+      retro_reset();
    }
 
    check_variables(PSP_CoreParameter());