diff --git a/BizHawk.Emulation.Cores/BizHawk.Emulation.Cores.csproj b/BizHawk.Emulation.Cores/BizHawk.Emulation.Cores.csproj
index 2e39d7e125..c047c7ed71 100644
--- a/BizHawk.Emulation.Cores/BizHawk.Emulation.Cores.csproj
+++ b/BizHawk.Emulation.Cores/BizHawk.Emulation.Cores.csproj
@@ -545,6 +545,7 @@
+
diff --git a/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/Mapper202.cs b/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/Mapper202.cs
new file mode 100644
index 0000000000..392fbe4e62
--- /dev/null
+++ b/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/Mapper202.cs
@@ -0,0 +1,61 @@
+using BizHawk.Common;
+using BizHawk.Common.NumberExtensions;
+
+namespace BizHawk.Emulation.Cores.Nintendo.NES
+{
+ // 150-in-1
+ // http://wiki.nesdev.com/w/index.php/INES_Mapper_202
+ public class Mapper202 : NES.NESBoardBase
+ {
+ private int _reg;
+ private bool _isprg32KMode;
+
+ public override bool Configure(NES.EDetectionOrigin origin)
+ {
+ switch (Cart.board_type)
+ {
+ case "MAPPER202":
+ break;
+ default:
+ return false;
+ }
+
+ return true;
+ }
+
+ public override void SyncState(Serializer ser)
+ {
+ base.SyncState(ser);
+ ser.Sync("reg", ref _reg);
+ ser.Sync("isPrg32kMode", ref _isprg32KMode);
+ }
+
+ public override void WritePRG(int addr, byte value)
+ {
+ _reg = (addr >> 1) & 7;
+ _isprg32KMode = addr.Bit(0) && addr.Bit(3);
+
+ SetMirrorType(addr.Bit(0) ? EMirrorType.Horizontal : EMirrorType.Vertical);
+ }
+
+ public override byte ReadPRG(int addr)
+ {
+ if (_isprg32KMode)
+ {
+ return ROM[((_reg >> 1) * 0x8000) + (addr & 0x7FFF)];
+ }
+
+ return ROM[(_reg * 0x4000) + (addr & 0x3FFF)];
+ }
+
+ public override byte ReadPPU(int addr)
+ {
+ if (addr < 0x2000)
+ {
+ return VROM[(_reg * 0x2000) + (addr & 0x1FFF)];
+ }
+
+ return base.ReadPPU(addr);
+ }
+ }
+}