diff --git a/BizHawk.Emulation/BizHawk.Emulation.csproj b/BizHawk.Emulation/BizHawk.Emulation.csproj
index f7e4ce4a79..8395c1f06a 100644
--- a/BizHawk.Emulation/BizHawk.Emulation.csproj
+++ b/BizHawk.Emulation/BizHawk.Emulation.csproj
@@ -162,6 +162,7 @@
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper201.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper203.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper207.cs" />
+    <Compile Include="Consoles\Nintendo\NES\Boards\Mapper225.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper226.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper227.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper230.cs" />
diff --git a/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/Mapper225.cs b/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/Mapper225.cs
new file mode 100644
index 0000000000..8dd19278eb
--- /dev/null
+++ b/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/Mapper225.cs
@@ -0,0 +1,123 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace BizHawk.Emulation.Consoles.Nintendo
+{
+	class Mapper225 : NES.NESBoardBase
+	{
+		/*
+		Here are Disch's original notes:  
+		========================
+		=  Mapper 225          =
+		========================
+
+		Example Games:
+		--------------------------
+		52 Games
+		58-in-1
+		64-in-1
+
+
+		Registers:
+		---------------------------
+
+		$5800-5803:  [.... RRRR]  RAM  (readable/writable)
+		(16 bits of RAM -- 4 bits in each of the 4 regs)
+		$5804-5FFF:    mirrors $5800-5803
+
+		$8000-FFFF:  A~[.HMO PPPP PPCC CCCC]
+		H = High bit (acts as bit 7 for PRG and CHR regs)
+		M = Mirroring (0=Vert, 1=Horz)
+		O = PRG Mode
+		P = PRG Reg
+		C = CHR Reg
+
+
+		CHR Setup:
+		---------------------------
+
+		$0000   $0400   $0800   $0C00   $1000   $1400   $1800   $1C00 
+					+---------------------------------------------------------------+
+		CHR Mode 0: |                             $8000                             |
+					+---------------------------------------------------------------+
+
+
+		PRG Setup:
+		---------------------------
+
+					  $8000   $A000   $C000   $E000  
+					+-------------------------------+
+		PRG Mode 0: |            <$8000>            |
+					+-------------------------------+
+		PRG Mode 1: |     $8000     |     $8000     |
+					+---------------+---------------+
+		*/
+
+		bool prg_mode = false;
+		int chr_reg;
+		int prg_reg;
+
+		public override bool Configure(NES.EDetectionOrigin origin)
+		{
+			switch (Cart.board_type)
+			{
+				case "MAPPER225":
+					break;
+				default:
+					return false;
+			}
+
+			SetMirrorType(EMirrorType.Vertical);
+
+			return true;
+		}
+
+		public override void SyncState(Serializer ser)
+		{
+			ser.Sync("prg_reg", ref prg_reg);
+			ser.Sync("chr_reg", ref chr_reg);
+			ser.Sync("prg_mode", ref prg_mode);
+			base.SyncState(ser);
+		}
+
+		public override void WritePRG(int addr, byte value)
+		{
+			prg_mode = addr.Bit(12);
+
+			if (addr.Bit(13))
+			{
+				SetMirrorType(EMirrorType.Horizontal);
+			}
+			else
+			{
+				SetMirrorType(EMirrorType.Vertical);
+			}
+			int high = (addr & 0x4000) >> 8;
+			prg_reg = (addr >> 6) & 0x3F | high;
+			chr_reg = addr & 0x3F | high;
+		}
+
+		public override byte ReadPRG(int addr)
+		{
+			if (prg_mode)
+			{
+				return ROM[((prg_reg >> 1) * 0x8000) + addr];
+			}
+			else
+			{
+				return ROM[(prg_reg * 0x4000) + (addr & 0x3FFF)];
+			}
+		}
+
+		public override byte ReadPPU(int addr)
+		{
+			if (addr < 0x2000)
+			{
+				return VROM[(chr_reg * 0x2000) + addr];
+			}
+			return base.ReadPPU(addr);
+		}
+	}
+}