diff --git a/BizHawk.Emulation.Cores/BizHawk.Emulation.Cores.csproj b/BizHawk.Emulation.Cores/BizHawk.Emulation.Cores.csproj
index 3049b377d5..e0f1537eca 100644
--- a/BizHawk.Emulation.Cores/BizHawk.Emulation.Cores.csproj
+++ b/BizHawk.Emulation.Cores/BizHawk.Emulation.Cores.csproj
@@ -640,6 +640,7 @@
     <Compile Include="Consoles\Nintendo\NES\Boards\TENGEN_800008.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\UNIF\UNIF-DREAMTECH01.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\UNIF\UNIF_BMC-190in1.cs" />
+    <Compile Include="Consoles\Nintendo\NES\Boards\UNIF\UNIF_BMC-8157.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\UNIF\UNIF_BMC-A65AS.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\UNIF\UNIF_BMC-BS-5.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\UNIF\UNIF_BMC-GS-2004.cs" />
diff --git a/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/UNIF/UNIF_BMC-8157.cs b/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/UNIF/UNIF_BMC-8157.cs
new file mode 100644
index 0000000000..7b32ea5c39
--- /dev/null
+++ b/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/UNIF/UNIF_BMC-8157.cs
@@ -0,0 +1,64 @@
+using BizHawk.Common;
+
+namespace BizHawk.Emulation.Cores.Nintendo.NES
+{
+	// 4-in-1 1993 (CK-001) [U][!].unf
+	public class UNIF_BMC_8157 : NES.NESBoardBase
+	{
+		[MapperProp]
+		public bool _4in1Mode;
+
+		private int _cmdreg;
+
+		private int _prgMask16k;
+
+		public override bool Configure(NES.EDetectionOrigin origin)
+		{
+			switch (Cart.board_type)
+			{
+				case "UNIF_BMC-8157":
+					break;
+				default:
+					return false;
+			}
+
+			_prgMask16k = Cart.prg_size / 16 - 1;
+
+			AutoMapperProps.Apply(this);
+
+			return true;
+		}
+
+		public override void SyncState(Serializer ser)
+		{
+			base.SyncState(ser);
+			ser.Sync("cmdreg", ref _cmdreg);
+			ser.Sync("4in1Mode", ref _4in1Mode);
+		}
+
+		public override void WritePRG(int addr, byte value)
+		{
+			_cmdreg = addr;
+			int mir = ((_cmdreg & 2) >> 1) ^ 1;
+			SetMirrorType(mir == 1 ? EMirrorType.Vertical : EMirrorType.Horizontal);
+		}
+
+		public override byte ReadPRG(int addr)
+		{
+			if (_4in1Mode)
+			{
+				if (((_cmdreg & 0x100) > 0) && Cart.prg_size < 1024)
+				{
+					addr = (addr & 0xFFF0) + (1);
+				}
+			}
+
+			int basei = ((_cmdreg & 0x060) | ((_cmdreg & 0x100) >> 1)) >> 2;
+			int bank = (_cmdreg & 0x01C) >> 2;
+			int lbank = ((_cmdreg & 0x200) > 0) ? 7 : (((_cmdreg & 0x80) > 0) ? bank : 0);
+
+			int final = basei | (addr < 0x4000 ? bank : lbank);
+			return ROM[((final & _prgMask16k) * 0x4000) + (addr & 0x3FFF)];
+		}
+	}
+}