diff --git a/BizHawk.Emulation/BizHawk.Emulation.csproj b/BizHawk.Emulation/BizHawk.Emulation.csproj
index 117d3149fc..0e34513b07 100644
--- a/BizHawk.Emulation/BizHawk.Emulation.csproj
+++ b/BizHawk.Emulation/BizHawk.Emulation.csproj
@@ -187,6 +187,7 @@
+
diff --git a/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/MMC3_family/Mapper052.cs b/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/MMC3_family/Mapper052.cs
new file mode 100644
index 0000000000..45a9c53ff4
--- /dev/null
+++ b/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/MMC3_family/Mapper052.cs
@@ -0,0 +1,142 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace BizHawk.Emulation.Consoles.Nintendo
+{
+ class Mapper52 : MMC3Board_Base
+ {
+ //http://wiki.nesdev.com/w/index.php/INES_Mapper_052
+
+ bool lock_regs = false;
+ bool prg_block_size = false;
+ bool chr_block_size = false;
+ int prg_or = 0;
+ int chr_or = 0;
+
+ public override bool Configure(NES.EDetectionOrigin origin)
+ {
+ switch (Cart.board_type)
+ {
+ case "MAPPER052":
+ break;
+ default:
+ return false;
+ }
+
+ BaseSetup();
+ return true;
+ }
+
+ public override void SyncState(Serializer ser)
+ {
+ ser.Sync("lock_regs", ref lock_regs);
+ ser.Sync("prg_block_size", ref prg_block_size);
+ ser.Sync("chr_block_size", ref chr_block_size);
+ ser.Sync("prg_or", ref prg_or);
+ ser.Sync("chr_or", ref chr_or);
+ base.SyncState(ser);
+ }
+
+ public override void NESSoftReset()
+ {
+ lock_regs = false;
+ prg_block_size = false;
+ chr_block_size = false;
+ prg_or = 0;
+ chr_or = 0;
+ base.NESSoftReset();
+ }
+
+ public override void WriteWRAM(int addr, byte value)
+ {
+ if (lock_regs)
+ {
+ base.WriteWRAM(addr, value);
+ }
+ else
+ {
+ lock_regs = value.Bit(4);
+ prg_block_size = value.Bit(3);
+ chr_block_size = value.Bit(6);
+ int combo = (value >> 2) & 0x01;
+ prg_or = ((value >> 1) & 0x01) << 5;
+ prg_or |= (value & 0x01) << 6;
+ prg_or |= (combo << 7);
+ chr_or = ((value >> 4) & 0x01) << 7;
+ chr_or |= combo << 8;
+ chr_or |= ((value >> 5) & 0x01) << 9;
+ }
+ }
+
+ public override byte ReadPRG(int addr)
+ {
+ int bank_8k = Get_PRGBank_8K(addr);
+ bank_8k &= PRG_AND();
+ bank_8k |= PRG_OR();
+ bank_8k &= prg_mask;
+ addr = (bank_8k << 13) | (addr & 0x1FFF);
+ return ROM[addr];
+ }
+
+ private int PRG_AND()
+ {
+ if (prg_block_size)
+ {
+ return 0x0F;
+ }
+ else
+ {
+ return 0x1F;
+ }
+ }
+
+ private int PRG_OR()
+ {
+ if (prg_block_size)
+ {
+ return prg_or;
+ }
+ else
+ {
+ return (prg_or & 0x60);
+ }
+ }
+
+ 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;
+ }
+
+ private int CHR_AND()
+ {
+ if (chr_block_size)
+ {
+ return 0x7F;
+ }
+ else
+ {
+ return 0xFF;
+ }
+ }
+
+ private int CHR_OR()
+ {
+ if (chr_block_size)
+ {
+ return chr_or;
+ }
+ else
+ {
+ return (chr_or & 0x300);
+ }
+ }
+ }
+}