diff --git a/BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/LibmGBA.cs b/BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/LibmGBA.cs
index c3f3064fca..a59af3dc2c 100644
--- a/BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/LibmGBA.cs
+++ b/BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/LibmGBA.cs
@@ -140,6 +140,9 @@ 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 BizSetRegister(IntPtr ctx, int index, int value);
+
 		[DllImport(dll, CallingConvention = cc)]
 		public static extern void BizWriteBus(IntPtr ctx, uint addr, byte val);
 
diff --git a/BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/MGBAHawk.IDebuggable.cs b/BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/MGBAHawk.IDebuggable.cs
index 2726f8ec96..0936bcd607 100644
--- a/BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/MGBAHawk.IDebuggable.cs
+++ b/BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/MGBAHawk.IDebuggable.cs
@@ -1,6 +1,5 @@
 using System;
 using System.Collections.Generic;
-
 using BizHawk.Emulation.Common;
 
 namespace BizHawk.Emulation.Cores.Nintendo.GBA
@@ -23,7 +22,33 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBA
 		[FeatureNotImplemented]
 		public void SetCpuRegister(string register, int value)
 		{
-			throw new NotImplementedException();
+			int index = register?.ToUpper() switch
+			{
+				"R0" => 0,
+				"R1" => 1,
+				"R2" => 2,
+				"R3" => 3,
+				"R4" => 4,
+				"R5" => 5,
+				"R6" => 6,
+				"R7" => 7,
+				"R8" => 8,
+				"R9" => 9,
+				"R10" => 10,
+				"R11" => 11,
+				"R12" => 12,
+				"R13" => 13,
+				"R14" => 14,
+				"R15" => 15,
+				"CPSR" => 16,
+				"SPSR" => 17,
+				_=> -1
+			};
+
+			if (index != -1)
+			{
+				LibmGBA.BizSetRegister(Core, index, value);
+			}
 		}
 
 		[FeatureNotImplemented]
diff --git a/mgba b/mgba
index c70b9a56dc..13d650da6c 160000
--- a/mgba
+++ b/mgba
@@ -1 +1 @@
-Subproject commit c70b9a56dc3e197f400061b9635d4d9c1996e282
+Subproject commit 13d650da6c89d5f82f03b73928b7d9f1643990c6
diff --git a/output/dll/mgba.dll b/output/dll/mgba.dll
index eeabb7d39b..0316c5c775 100644
Binary files a/output/dll/mgba.dll and b/output/dll/mgba.dll differ