diff --git a/Source/Core/Core/HW/MMIO.h b/Source/Core/Core/HW/MMIO.h
index 10bba4a6c8..0a4a1a5d04 100644
--- a/Source/Core/Core/HW/MMIO.h
+++ b/Source/Core/Core/HW/MMIO.h
@@ -9,6 +9,7 @@
 #include <type_traits>
 
 #include "Common/Common.h"
+#include "Core/ConfigManager.h"
 #include "Core/HW/MMIOHandlers.h"
 
 namespace MMIO
@@ -40,8 +41,18 @@ const u32 NUM_MMIOS = NUM_BLOCKS * BLOCK_SIZE;
 // interface.
 inline bool IsMMIOAddress(u32 address)
 {
-	return ((address & 0xFE7F0000) == 0xCC000000) &&
-	       ((address & 0x0000FFFF) != 0x00008000);
+	if (address == 0xCC008000)
+		return false; // WG Pipe
+	if ((address & 0xFFFF0000) == 0xCC000000)
+		return true; // GameCube MMIOs
+
+	if(SConfig::GetInstance().m_LocalCoreStartupParameter.bWii)
+	{
+		return ((address & 0xFFFF0000) == 0xCD000000) || // Wii MMIOs
+		       ((address & 0xFFFF0000) == 0xCD800000);   // Mirror of Wii MMIOs
+	}
+
+	return false;
 }
 
 // Compute the internal unique ID for a given MMIO address. This ID is computed
diff --git a/Source/UnitTests/Core/MMIOTest.cpp b/Source/UnitTests/Core/MMIOTest.cpp
index f9173ce0c4..bb7f1c4714 100644
--- a/Source/UnitTests/Core/MMIOTest.cpp
+++ b/Source/UnitTests/Core/MMIOTest.cpp
@@ -25,11 +25,24 @@ TEST(UniqueID, UniqueEnough)
 
 TEST(IsMMIOAddress, SpecialAddresses)
 {
+	SConfig::Init();
+	SConfig::GetInstance().m_LocalCoreStartupParameter.bWii = true;
+
 	// WG Pipe address, should not be handled by MMIO.
 	EXPECT_FALSE(MMIO::IsMMIOAddress(0xCC008000));
 
 	// Memory zone used by games using the "MMU Speedhack".
 	EXPECT_FALSE(MMIO::IsMMIOAddress(0xE0000000));
+
+	// Uncached mirror of MEM1, shouldn't be handled by MMIO
+	EXPECT_FALSE(MMIO::IsMMIOAddress(0xC0000000));
+
+	// And lets check some valid addresses too
+	EXPECT_TRUE(MMIO::IsMMIOAddress(0xCC0000E0)); // Gamecube MMIOs
+	EXPECT_TRUE(MMIO::IsMMIOAddress(0xCD00008C)); // Wii MMIOs
+	EXPECT_TRUE(MMIO::IsMMIOAddress(0xCD800F10)); // Mirror of Wii MMIOs
+
+	SConfig::Shutdown();
 }
 
 class MappingTest : public testing::Test