diff --git a/Core/MemMap.cpp b/Core/MemMap.cpp
index dff978cf75..815b4c1f0e 100644
--- a/Core/MemMap.cpp
+++ b/Core/MemMap.cpp
@@ -71,6 +71,11 @@ u8 *m_pUncachedKernelRAM[3];
 static u8 *m_pPhysicalVRAM[4];
 static u8 *m_pUncachedVRAM[4];
 
+// Hardware registers are mapped at 0xbc000000 and forwards (physical address 0x1C000000, but we need
+// the 0x80000000 kernel flag and 0x40000000 uncached flag for these). Exception vectors are at 0xbfc00000.
+// Since we do HLE emulation, we currently don't bother with any of that.
+// Some limited documentation here: https://www.psdevwiki.com/psp/Hardware_Registers#Introduction
+
 // Holds the ending address of the PSP's user space.
 // Required for HD Remasters to work properly.
 // This replaces RAM_NORMAL_SIZE at runtime.
diff --git a/libretro/libretro.cpp b/libretro/libretro.cpp
index 72bc15fb8a..974f78d50c 100644
--- a/libretro/libretro.cpp
+++ b/libretro/libretro.cpp
@@ -27,6 +27,7 @@
 #include "Core/Config.h"
 #include "Core/ConfigValues.h"
 #include "Core/Core.h"
+#include "Core/MIPS/MIPS.h"
 #include "Core/HLE/sceCtrl.h"
 #include "Core/HLE/sceUtility.h"
 #include "Core/HLE/__sceAudio.h"