diff --git a/BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/LibmGBA.cs b/BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/LibmGBA.cs
index 6c4e22442c..13467e19d2 100644
--- a/BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/LibmGBA.cs
+++ b/BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/LibmGBA.cs
@@ -132,5 +132,12 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBA
 
 		[DllImport(dll, CallingConvention = cc)]
 		public static extern void BizGetRegisters(IntPtr ctx, int[] dest);
+
+		[DllImport(dll, CallingConvention = cc)]
+		public static extern void BizWriteBus(IntPtr ctx, uint addr, byte val);
+
+		[DllImport(dll, CallingConvention = cc)]
+		public static extern byte BizReadBus(IntPtr ctx, uint addr);
+
 	}
 }
diff --git a/BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/MGBAHawk.IMemoryDomains.cs b/BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/MGBAHawk.IMemoryDomains.cs
index 06083eb0da..730e339447 100644
--- a/BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/MGBAHawk.IMemoryDomains.cs
+++ b/BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/MGBAHawk.IMemoryDomains.cs
@@ -34,6 +34,28 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBA
 			mm.Add(_sram = new MemoryDomainIntPtr("SRAM", le, IntPtr.Zero, 0, true, 4)); // size will be fixed in wireup
 			mm.Add(_cwram = new MemoryDomainDelegate("Combined WRAM", (256 + 32) * 1024, le, null, null, 4));
 
+			mm.Add(new MemoryDomainDelegate("System Bus", 0x10000000, le,
+				delegate (long addr)
+				{
+					var a = (uint)addr;
+					if (a >= 0x10000000)
+					{
+						throw new ArgumentOutOfRangeException();
+					}
+
+					return LibmGBA.BizReadBus(_core, a);
+				},
+				delegate (long addr, byte val)
+				{
+					var a = (uint)addr;
+					if (a >= 0x10000000)
+					{
+						throw new ArgumentOutOfRangeException();
+					}
+
+					LibmGBA.BizWriteBus(_core, a, val);
+				}, 4));
+
 			_memoryDomains = new MemoryDomainList(mm);
 			WireMemoryDomainPointers();
 		}
@@ -55,7 +77,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBA
 
 			// special combined ram memory domain
 			_cwram.Peek =
-				delegate(long addr)
+				delegate (long addr)
 				{
 					if (addr < 0 || addr >= (256 + 32) * 1024)
 					{
@@ -70,7 +92,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBA
 					return PeekWRAM(s.wram, addr);
 				};
 			_cwram.Poke =
-				delegate(long addr, byte val)
+				delegate (long addr, byte val)
 				{
 					if (addr < 0 || addr >= (256 + 32) * 1024)
 					{
diff --git a/output/dll/mgba.dll b/output/dll/mgba.dll
index 3d18ea0be9..123320afe5 100644
Binary files a/output/dll/mgba.dll and b/output/dll/mgba.dll differ