diff --git a/BizHawk.Emulation/BizHawk.Emulation.csproj b/BizHawk.Emulation/BizHawk.Emulation.csproj
index da3ced6aef..28f8a16142 100644
--- a/BizHawk.Emulation/BizHawk.Emulation.csproj
+++ b/BizHawk.Emulation/BizHawk.Emulation.csproj
@@ -204,6 +204,7 @@
     <Compile Include="Consoles\Nintendo\NES\Boards\BANDAI_74_161_161_32.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\BxROM.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\Camerica.cs" />
+    <Compile Include="Consoles\Nintendo\NES\Boards\Mapper028.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\CNROM.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\CPROM.cs">
       <SubType>Code</SubType>
diff --git a/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/Mapper028.cs b/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/Mapper028.cs
new file mode 100644
index 0000000000..761a9e3342
--- /dev/null
+++ b/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/Mapper028.cs
@@ -0,0 +1,196 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace BizHawk.Emulation.Consoles.Nintendo
+{
+	// http://wiki.nesdev.com/w/index.php/User:Tepples/Multi-discrete_mapper
+	public class Mapper028 : NES.NESBoardBase
+	{
+		// config
+		int chr_mask_8k;
+		int prg_mask_16k;
+
+		// state
+		int reg;
+		int chr;
+		int prg;
+		int mode;
+		int outer;
+
+		// regennable state
+		int prglo;
+		int prghi;
+
+		public override bool Configure(NES.EDetectionOrigin origin)
+		{
+			switch (Cart.board_type)
+			{
+				case "MAPPER028":
+					break;
+				default:
+					return false;
+			}
+			AssertPrg(32, 64, 128, 256, 512, 1024, 2048);
+			AssertChr(0);
+			chr_mask_8k = Cart.chr_size / 8 - 1;
+			prg_mask_16k = Cart.prg_size / 16 - 1;
+			Cart.wram_size = 0;
+			Cart.vram_size = 32;
+			return true;
+		}
+
+		void Sync()
+		{
+			int outb = outer << 1;
+			// this can probably be rolled up, but i have no motivation to do so
+			// until it's been tested
+			switch (mode & 0x3c)
+			{
+				// 32K modes
+				case 0x00:
+				case 0x04:
+					prglo = outb;
+					prghi = outb | 1;
+					break;
+				case 0x10:
+				case 0x14:
+					prglo = outb & ~2 | prg & 2;
+					prghi = outb & ~2 | prg & 2 | 1;
+					break;
+				case 0x20:
+				case 0x24:
+					prglo = outb & ~6 | prg & 6;
+					prghi = outb & ~6 | prg & 6 | 1;
+					break;
+				case 0x30:
+				case 0x34:
+					prglo = outb & ~14 | prg & 14;
+					prghi = outb & ~14 | prg & 14 | 1;
+					break;
+				// bottom fixed modes
+				case 0x08:
+					prglo = outb;
+					prghi = outb | prg & 1;
+					break;
+				case 0x18:
+					prglo = outb;
+					prghi = outb & ~2 | prg & 3;
+					break;
+				case 0x28:
+					prglo = outb;
+					prghi = outb & ~6 | prg & 7;
+					break;
+				case 0x38:
+					prglo = outb;
+					prghi = outb & ~14 | prg & 15;
+					break;
+				// top fixed modes
+				case 0x0c:
+					prglo = outb | prg & 1;
+					prghi = outb | 1;
+					break;
+				case 0x1c:
+					prglo = outb & ~2 | prg & 3;
+					prghi = outb | 1;
+					break;
+				case 0x2c:
+					prglo = outb & ~6 | prg & 7;
+					prghi = outb | 1;
+					break;
+				case 0x3c:
+					prglo = outb & ~14 | prg & 15;
+					prghi = outb | 1;
+					break;
+			}
+			prglo &= prg_mask_16k;
+			prghi &= prg_mask_16k;
+		}
+
+		void Mirror(byte value)
+		{
+			if ((mode & 2) == 0)
+			{
+				mode &= 0xfe;
+				mode |= value >> 4 & 1;
+			}
+			SyncMirror();
+		}
+
+		void SyncMirror()
+		{
+			switch (mode & 3)
+			{
+				case 0: SetMirrorType(EMirrorType.OneScreenA); break;
+				case 1: SetMirrorType(EMirrorType.OneScreenB); break;
+				case 2: SetMirrorType(EMirrorType.Vertical); break;
+				case 3: SetMirrorType(EMirrorType.Horizontal); break;
+			}
+		}
+
+		public override void WriteEXP(int addr, byte value)
+		{
+			if (addr >= 0x1000)
+				reg = value & 0x81;
+		}
+
+		public override void WritePRG(int addr, byte value)
+		{
+			switch (reg)
+			{
+				case 0x00:
+					chr = value & 3;
+					Mirror(value);
+					break;
+				case 0x01:
+					prg = value & 15;
+					Mirror(value);
+					Sync();
+					break;
+				case 0x80:
+					mode = value & 63;
+					SyncMirror();
+					Sync();
+					break;
+				case 0x81:
+					outer = value & 63;
+					Sync();
+					break;
+			}
+		}
+
+		public override byte ReadPPU(int addr)
+		{
+			if (addr < 0x2000)
+				return VRAM[addr | chr << 13];
+			else
+				return base.ReadPPU(addr);
+		}
+
+		public override void WritePPU(int addr, byte value)
+		{
+			if (addr < 0x2000)
+				VRAM[addr | chr << 13] = value;
+			else
+				base.WritePPU(addr, value);
+		}
+
+		public override byte ReadPRG(int addr)
+		{
+			return ROM[(addr & 0x3fff) | (addr < 0x4000 ? prglo : prghi) << 14];
+		}
+
+		public override void SyncState(Serializer ser)
+		{
+			base.SyncState(ser);
+			ser.Sync("reg", ref reg);
+			ser.Sync("chr", ref chr);
+			ser.Sync("prg", ref prg);
+			ser.Sync("mode", ref mode);
+			ser.Sync("outer", ref outer);
+			if (!ser.IsWriter)
+				Sync();
+		}
+	}
+}