diff --git a/src/mame/drivers/namcos10.c b/src/mame/drivers/namcos10.c
index adbc50d5029..1cc4dce83f7 100644
--- a/src/mame/drivers/namcos10.c
+++ b/src/mame/drivers/namcos10.c
@@ -554,8 +554,10 @@ DRIVER_INIT_MEMBER(namcos10_state,knpuzzle)
 
 DRIVER_INIT_MEMBER(namcos10_state,startrgn)
 {
+	int regSize = machine().root_device().memregion("user2")->bytes();
 	decrypt_bios(machine(), "user2", 0x008400, 0x028000, 0x6, 0x5, 0x4, 0x7, 0x1, 0x3, 0x0, 0x2, 0xc, 0xd, 0xe, 0xf, 0x8, 0xb, 0xa, 0x9);
 	decrypt_bios(machine(), "user2", 0x0b4000, 0xfdc000, 0x6, 0x5, 0x4, 0x7, 0x1, 0x3, 0x0, 0x2, 0xc, 0xd, 0xe, 0xf, 0x8, 0xb, 0xa, 0x9);
+	decrypt_bios(machine(), "user2", 0x1000000, regSize, 0x6, 0x7, 0x4, 0x5, 0x0, 0x1, 0x3, 0x2, 0xd, 0xc, 0xf, 0xe, 0x8, 0x9, 0xb, 0xa);
 	memn_driver_init();
 }
 
@@ -596,8 +598,10 @@ DRIVER_INIT_MEMBER(namcos10_state,nflclsfb)
 
 DRIVER_INIT_MEMBER(namcos10_state,konotako)
 {
+	int regSize = machine().root_device().memregion("user2")->bytes();
 	decrypt_bios(machine(), "user2", 0x008400, 0x028000, 0x6, 0x7, 0x4, 0x5, 0x0, 0x1, 0x3, 0x2, 0xd, 0xc, 0xf, 0xe, 0x8, 0x9, 0xb, 0xa);
 	decrypt_bios(machine(), "user2", 0x0b4000, 0xfdc000, 0x6, 0x7, 0x4, 0x5, 0x0, 0x1, 0x3, 0x2, 0xd, 0xc, 0xf, 0xe, 0x8, 0x9, 0xb, 0xa);
+	decrypt_bios(machine(), "user2", 0x1000000, regSize, 0x6, 0x7, 0x4, 0x5, 0x0, 0x1, 0x3, 0x2, 0xd, 0xc, 0xf, 0xe, 0x8, 0x9, 0xb, 0xa);
 	memn_driver_init();
 }