diff --git a/Source/Core/Core/HW/DVD/DVDInterface.cpp b/Source/Core/Core/HW/DVD/DVDInterface.cpp
index 857c6edb91..8f00b955d2 100644
--- a/Source/Core/Core/HW/DVD/DVDInterface.cpp
+++ b/Source/Core/Core/HW/DVD/DVDInterface.cpp
@@ -606,7 +606,7 @@ bool UpdateRunningGameMetadata(std::optional<u64> title_id)
   return DVDThread::UpdateRunningGameMetadata(IOS::HLE::DIDevice::GetCurrentPartition(), title_id);
 }
 
-void RegisterMMIO(MMIO::Mapping* mmio, u32 base)
+void RegisterMMIO(MMIO::Mapping* mmio, u32 base, bool is_wii)
 {
   mmio->Register(base | DI_STATUS_REGISTER, MMIO::DirectRead<u32>(&s_DISR.Hex),
                  MMIO::ComplexWrite<u32>([](u32, u32 val) {
@@ -657,8 +657,18 @@ void RegisterMMIO(MMIO::Mapping* mmio, u32 base)
   // DMA related registers. Mostly direct accesses (+ masking for writes to
   // handle things like address alignment) and complex write on the DMA
   // control register that will trigger the DMA.
+
+  // The DMA address register masks away the top and bottom bits on GameCube, but only the top bits
+  // on Wii (which can be observed by reading back the register; this difference probably exists due
+  // to the existence of MEM2). The behavior of GameCube mode on a Wii (via MIOS/booting form the
+  // system menu) has not been tested yet. Note that RegisterMMIO does not get re-called when
+  // switching to GameCube mode; we handle this difference by applying the masking when using the
+  // GameCube's DI MMIO address (0x0C006000) but not applying it when using the Wii's DI MMIO
+  // address (0x0D006000), although we allow writes to both of these addresses if Dolphin was
+  // started in Wii mode. (Also, normally in Wii mode the DI MMIOs are only written by the
+  // IOS /dev/di module, but we *do* emulate /dev/di writing the DI MMIOs.)
   mmio->Register(base | DI_DMA_ADDRESS_REGISTER, MMIO::DirectRead<u32>(&s_DIMAR),
-                 MMIO::DirectWrite<u32>(&s_DIMAR, ~0x1F));
+                 MMIO::DirectWrite<u32>(&s_DIMAR, is_wii ? ~0x1F : ~0xFC00001F));
   mmio->Register(base | DI_DMA_LENGTH_REGISTER, MMIO::DirectRead<u32>(&s_DILENGTH),
                  MMIO::DirectWrite<u32>(&s_DILENGTH, ~0x1F));
   mmio->Register(base | DI_DMA_CONTROL_REGISTER, MMIO::DirectRead<u32>(&s_DICR.Hex),
diff --git a/Source/Core/Core/HW/DVD/DVDInterface.h b/Source/Core/Core/HW/DVD/DVDInterface.h
index 80dbbc5f1b..930da55b12 100644
--- a/Source/Core/Core/HW/DVD/DVDInterface.h
+++ b/Source/Core/Core/HW/DVD/DVDInterface.h
@@ -113,7 +113,7 @@ void ResetDrive(bool spinup);
 void Shutdown();
 void DoState(PointerWrap& p);
 
-void RegisterMMIO(MMIO::Mapping* mmio, u32 base);
+void RegisterMMIO(MMIO::Mapping* mmio, u32 base, bool is_wii);
 
 void SetDisc(std::unique_ptr<DiscIO::VolumeDisc> disc,
              std::optional<std::vector<std::string>> auto_disc_change_paths);
diff --git a/Source/Core/Core/HW/Memmap.cpp b/Source/Core/Core/HW/Memmap.cpp
index f61e974bf3..e9b78f6383 100644
--- a/Source/Core/Core/HW/Memmap.cpp
+++ b/Source/Core/Core/HW/Memmap.cpp
@@ -141,14 +141,14 @@ static void InitMMIO(bool is_wii)
   ProcessorInterface::RegisterMMIO(mmio_mapping.get(), 0x0C003000);
   MemoryInterface::RegisterMMIO(mmio_mapping.get(), 0x0C004000);
   DSP::RegisterMMIO(mmio_mapping.get(), 0x0C005000);
-  DVDInterface::RegisterMMIO(mmio_mapping.get(), 0x0C006000);
+  DVDInterface::RegisterMMIO(mmio_mapping.get(), 0x0C006000, false);
   SerialInterface::RegisterMMIO(mmio_mapping.get(), 0x0C006400);
   ExpansionInterface::RegisterMMIO(mmio_mapping.get(), 0x0C006800);
   AudioInterface::RegisterMMIO(mmio_mapping.get(), 0x0C006C00);
   if (is_wii)
   {
     IOS::RegisterMMIO(mmio_mapping.get(), 0x0D000000);
-    DVDInterface::RegisterMMIO(mmio_mapping.get(), 0x0D006000);
+    DVDInterface::RegisterMMIO(mmio_mapping.get(), 0x0D006000, true);
     SerialInterface::RegisterMMIO(mmio_mapping.get(), 0x0D006400);
     ExpansionInterface::RegisterMMIO(mmio_mapping.get(), 0x0D006800);
     AudioInterface::RegisterMMIO(mmio_mapping.get(), 0x0D006C00);