diff --git a/BizHawk.Emulation/BizHawk.Emulation.csproj b/BizHawk.Emulation/BizHawk.Emulation.csproj
index f28b353438..117d3149fc 100644
--- a/BizHawk.Emulation/BizHawk.Emulation.csproj
+++ b/BizHawk.Emulation/BizHawk.Emulation.csproj
@@ -177,6 +177,7 @@
+
diff --git a/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/Mapper50.cs b/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/Mapper50.cs
new file mode 100644
index 0000000000..ee87270a06
--- /dev/null
+++ b/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/Mapper50.cs
@@ -0,0 +1,80 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace BizHawk.Emulation.Consoles.Nintendo
+{
+ class Mapper50 : NES.NESBoardBase
+ {
+ //http://wiki.nesdev.com/w/index.php/INES_Mapper_050
+
+ byte prg_bank;
+ int prg_bank_mask_8k;
+
+ public override bool Configure(NES.EDetectionOrigin origin)
+ {
+ //analyze board type
+ switch (Cart.board_type)
+ {
+ case "MAPPER050":
+ break;
+ default:
+ return false;
+ }
+ prg_bank = 0;
+ prg_bank_mask_8k = Cart.prg_size / 8 - 1;
+
+ return true;
+ }
+
+ public override void SyncState(Serializer ser)
+ {
+ ser.Sync("prg_bank", ref prg_bank);
+ base.SyncState(ser);
+ }
+
+ public override void WriteEXP(int addr, byte value)
+ {
+ addr &= 0x0120;
+ if (addr == 0x0020)
+ {
+ //byte low = (byte)((value >> 1) & 0x03);
+ //byte middle = (byte)(value & 0x01);
+ //byte high = (byte)((value >> 3) & 0x01);
+ //prg_bank = (byte)(low | (middle << 2) | (high << 3));
+
+ prg_bank = (byte)(((value & 1) << 2) | ((value & 2) >> 1) | ((value & 4) >> 1) | (value & 8));
+
+ Console.WriteLine(prg_bank);
+ }
+ base.WriteEXP(addr, value);
+ }
+
+ public override byte ReadPRG(int addr)
+ {
+ if (addr < 0x2000)
+ {
+ return ROM[(0x08 * 0x2000) + (addr & 0x1FFF)];
+ }
+ else if (addr < 0x4000)
+ {
+ return ROM[(0x09 * 0x2000) + (addr & 0x1FFF)];
+ }
+ else if (addr < 0x6000)
+ {
+ int bank = (prg_bank & prg_bank_mask_8k);
+ return ROM[(bank * 0x2000) + (addr & 0x1FFF)];
+ }
+ else
+ {
+ return ROM[(0x0B * 0x2000) + (addr & 0x1FFF)];
+ }
+ }
+
+ public override byte ReadPPU(int addr)
+ {
+ return ROM[(0x0F * 0x2000) + (addr & 0x1FFF)];
+ }
+ }
+}