diff --git a/src/boards/466.c b/src/boards/466.c
new file mode 100644
index 0000000..a8ad361
--- /dev/null
+++ b/src/boards/466.c
@@ -0,0 +1,100 @@
+/* FCEUmm - NES/Famicom Emulator
+ *
+ * Copyright notice for this file:
+ *  Copyright (C) 2022
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include "mapinc.h"
+
+static uint8 regs[3];
+
+static SFORMAT StateRegs[] =
+{
+   { regs, 3, "EXPR" },
+   { 0 }
+};
+
+static DECLFR(Mapper466_ReadOB)
+{
+   return X.DB;
+}
+
+static void Mapper466_Sync(void)
+{
+   int prg =regs[1] <<5 | regs[0] <<1 &0x1E | regs[0] >>5 &1;
+   
+   /* Return open bus when selecting unpopulated PRG chip */
+   if (prg &0x20 && PRGsize[0] <1024*1024)
+	   SetReadHandler(0x8000, 0xFFFF, Mapper466_ReadOB);
+   else
+	   SetReadHandler(0x8000, 0xFFFF, CartBR);
+   
+   if (regs[0] &0x40)
+   {
+      if (regs[0] &0x10)
+      {
+         setprg16(0x8000, prg);
+         setprg16(0xC000, prg);
+      }
+      else
+      {
+         setprg32(0x8000, prg >>1);
+      }
+   }
+   else
+   {
+      setprg16(0x8000, prg &~7 | regs[2] &7);
+      setprg16(0xC000, prg &~7 |          7);
+   }
+   setprg8r(0x10, 0x6000, 0);
+   setchr8(0);
+   setmirror(regs[0] &0x80? MI_H: MI_V);
+}
+
+static DECLFW(Mapper466_Write5000)
+{
+   regs[A >>11 &1] =A &0xFF;
+   Mapper466_Sync();
+}
+
+static DECLFW(Mapper466_WriteLatch)
+{
+   regs[2] =V;
+   Mapper466_Sync();
+}
+
+static void Mapper466_Reset(void)
+{
+   regs[0] =regs[1] =0;
+   Mapper466_Sync();
+}
+
+static void Mapper466_Power(void)
+{
+   regs[0] =regs[1] =0;
+   Mapper466_Sync();
+   SetWriteHandler(0x5000, 0x5FFF, Mapper466_Write5000);
+   SetWriteHandler(0x8000, 0xFFFF, Mapper466_WriteLatch);
+   SetReadHandler(0x6000, 0xFFFF, CartBR);
+}
+
+void Mapper466_Init(CartInfo *info)
+{
+   info->Power       = Mapper466_Power;
+   info->Reset       = Mapper466_Reset;
+   AddExState(StateRegs, ~0, 0, 0);
+}
\ No newline at end of file
diff --git a/src/ines.c b/src/ines.c
index aee8aad..1d7f0b2 100644
--- a/src/ines.c
+++ b/src/ines.c
@@ -821,6 +821,7 @@ INES_BOARD_BEGIN()
 	INES_BOARD( "DS-9-27",                  452, Mapper452_Init         )
 	INES_BOARD( "K6C3001A",                 456, Mapper456_Init         )
 	INES_BOARD( "YH810X1",                 	463, Mapper463_Init         )
+	INES_BOARD( "Keybyte Computer",        	466, Mapper466_Init         )
 	INES_BOARD( "47-2",                 	467, Mapper467_Init         )
 	INES_BOARD( "SA-9602B",                 513, SA9602B_Init           )
 	INES_BOARD( "Brilliant Com Cocoma Pack", 516, Mapper516_Init        )
diff --git a/src/ines.h b/src/ines.h
index 6da5dd1..8a6d505 100644
--- a/src/ines.h
+++ b/src/ines.h
@@ -329,6 +329,7 @@ void Mapper444_Init(CartInfo *);
 void Mapper452_Init(CartInfo *);
 void Mapper456_Init(CartInfo *);
 void Mapper463_Init(CartInfo *);
+void Mapper466_Init(CartInfo *);
 void Mapper467_Init(CartInfo *);
 void Mapper516_Init(CartInfo *);
 void Mapper523_Init(CartInfo *);