diff --git a/BizHawk.Emulation/BizHawk.Emulation.csproj b/BizHawk.Emulation/BizHawk.Emulation.csproj
index 38751c3fee..f28b353438 100644
--- a/BizHawk.Emulation/BizHawk.Emulation.csproj
+++ b/BizHawk.Emulation/BizHawk.Emulation.csproj
@@ -149,6 +149,7 @@
     <Compile Include="Consoles\Nintendo\NES\Boards\JALECO_JF_17.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\JALECO_JF_19.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper015.cs" />
+    <Compile Include="Consoles\Nintendo\NES\Boards\Mapper045.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper057.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper058.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper069.cs" />
diff --git a/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/MMC3_family/MMC3.cs b/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/MMC3_family/MMC3.cs
index 31b9461855..25e36221cc 100644
--- a/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/MMC3_family/MMC3.cs
+++ b/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/MMC3_family/MMC3.cs
@@ -321,7 +321,7 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 			return mmc3.Get_PRGBank_8K(addr);
 		}
 
-		int MapCHR(int addr)
+		protected virtual int MapCHR(int addr)
 		{
 			int bank_1k = Get_CHRBank_1K(addr);
 			bank_1k &= chr_mask;
diff --git a/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/MMC3_family/Mapper205.cs b/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/MMC3_family/Mapper205.cs
index 351f1bf0a2..25d37af063 100644
--- a/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/MMC3_family/Mapper205.cs
+++ b/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/MMC3_family/Mapper205.cs
@@ -68,7 +68,7 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 			return ROM[addr];
 		}
 
-		int MapCHR(int addr)
+		int MapCHR2(int addr)
 		{
 			int bank_1k = Get_CHRBank_1K(addr);
 			bank_1k &= chr_mask;
@@ -99,7 +99,7 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 		{
 			if (addr < 0x2000)
 			{
-				addr = MapCHR(addr);
+				addr = MapCHR2(addr);
 				if (VROM != null)
 					return VROM[addr + extra_vrom];
 				else return VRAM[addr];
diff --git a/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/Mapper045.cs b/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/Mapper045.cs
new file mode 100644
index 0000000000..e7a95e382f
--- /dev/null
+++ b/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/Mapper045.cs
@@ -0,0 +1,142 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace BizHawk.Emulation.Consoles.Nintendo
+{
+	class Mapper045 : MMC3Board_Base
+	{
+		//http://wiki.nesdev.com/w/index.php/INES_Mapper_045
+
+		int chr_bank_mask_2k;
+		int prg_bank_mask_8k;
+		int cur_reg = 0;
+		ByteBuffer regs = new ByteBuffer(4);
+		bool lock_regs = false;
+
+		public override bool Configure(NES.EDetectionOrigin origin)
+		{
+			switch (Cart.board_type)
+			{
+				case "MAPPER045":
+					break;
+				default:
+					return false;
+			}
+
+			chr_bank_mask_2k = Cart.chr_size / 2 - 1;
+			prg_bank_mask_8k = Cart.prg_size / 8 - 1;
+			BaseSetup();
+			return true;
+		}
+
+		public override void Dispose()
+		{
+			regs.Dispose();
+			base.Dispose();
+		}
+
+		public override void SyncState(Serializer ser)
+		{
+			ser.Sync("regs", ref regs);
+			base.SyncState(ser);
+		}
+
+		public override void WriteWRAM(int addr, byte value)
+		{
+			if (lock_regs)
+			{
+				base.WriteWRAM(addr, value);
+			}
+			else
+			{
+				regs[cur_reg] = value;
+				IncrementCounter();
+				Sync45();
+			}
+		}
+
+		private void Sync45()
+		{
+			lock_regs = regs[3].Bit(6);
+		}
+
+		private void IncrementCounter()
+		{
+			if (cur_reg == 3)
+			{
+				cur_reg = 0;
+			}
+			else
+			{
+				cur_reg++;
+			}
+		}
+
+		public override void NESSoftReset()
+		{
+			lock_regs = false;
+			cur_reg = 0;
+			regs = new ByteBuffer(4);
+			base.NESSoftReset();
+		}
+
+		public override byte ReadPRG(int addr)
+		{
+			int bank_8k = Get_PRGBank_8K(addr);
+			bank_8k &= (regs[3] & 0x3F) ^ 0x3F;
+			bank_8k |= regs[1];
+			bank_8k &= prg_mask;
+			addr = (bank_8k << 13) | (addr & 0x1FFF);
+			return ROM[addr];
+		}
+
+		private int CHR_AND()
+		{
+			switch (regs[2] & 0x0F)
+			{
+				default:
+				case 0:
+				case 1:
+				case 2:
+				case 3:
+				case 4:
+				case 5:
+				case 6:
+				case 7:
+					return 0x00;
+				case 8:
+					return 0x01;
+				case 9:
+				case 0xA:
+				case 0xB:
+				case 0xC:
+				
+				case 0xD:
+					return 0x3F;
+				case 0xE:
+					return 0x7F;
+				case 0xF:
+					return 0xFF;
+			}
+		}
+
+		private int CHR_OR()
+		{
+			int x = regs[0] | ((regs[2] >> 4) << 8);
+			return x;
+		}
+
+		protected override int MapCHR(int addr)
+		{
+			int bank_1k = Get_CHRBank_1K(addr);
+			
+			bank_1k &= CHR_AND();
+			bank_1k |= CHR_OR();
+			bank_1k &= chr_mask;
+			addr = (bank_1k << 10) | (addr & 0x3FF);
+			return addr;
+		}
+	}
+}