diff --git a/BizHawk.Emulation/BizHawk.Emulation.csproj b/BizHawk.Emulation/BizHawk.Emulation.csproj
index 4033ed011a..ce93213dbe 100644
--- a/BizHawk.Emulation/BizHawk.Emulation.csproj
+++ b/BizHawk.Emulation/BizHawk.Emulation.csproj
@@ -155,6 +155,7 @@
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper027.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper038.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper040.cs" />
+    <Compile Include="Consoles\Nintendo\NES\Boards\Mapper041.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper042.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper045.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper057.cs" />
diff --git a/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/Mapper041.cs b/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/Mapper041.cs
new file mode 100644
index 0000000000..ebd75f5241
--- /dev/null
+++ b/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/Mapper041.cs
@@ -0,0 +1,73 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace BizHawk.Emulation.Consoles.Nintendo
+{
+	// caltron 6 in 1
+	public class Mapper041 : NES.NESBoardBase
+	{
+		int prg;
+		int chr;
+		bool regenable;
+
+		public override bool Configure(NES.EDetectionOrigin origin)
+		{
+			switch (Cart.board_type)
+			{
+				case "MAPPER041":
+				case "MLT-CALTRON6IN1":
+					break;
+				default:
+					return false;
+			}
+			AssertPrg(256);
+			AssertChr(128);
+			SetMirrorType(Cart.pad_h, Cart.pad_v);
+			return true;
+		}
+
+		public override void WriteWRAM(int addr, byte value)
+		{
+			if (addr < 0x800)
+			{
+				prg = addr & 7;
+				SetMirrorType((addr & 32) != 0 ? EMirrorType.Horizontal : EMirrorType.Vertical);
+				regenable = (addr & 4) != 0;
+				chr &= 3;
+				chr |= (addr >> 1) & 0xc;
+			}
+		}
+
+		public override void WritePRG(int addr, byte value)
+		{
+			if (regenable)
+			{
+				chr &= 0xc;
+				chr |= addr & 3;
+			}
+		}
+
+		public override byte ReadPPU(int addr)
+		{
+			if (addr < 0x2000)
+				return VROM[addr | chr << 13];
+			else
+				return base.ReadPPU(addr);
+		}
+
+		public override byte ReadPRG(int addr)
+		{
+			return ROM[addr | prg << 15];
+		}
+
+		public override void SyncState(Serializer ser)
+		{
+			base.SyncState(ser);
+			ser.Sync("prg", ref prg);
+			ser.Sync("chr", ref chr);
+			ser.Sync("regenable", ref regenable);
+		}
+	}
+}