diff --git a/src/mame/drivers/einstein.cpp b/src/mame/drivers/einstein.cpp index a736d2e7fee..701253a1978 100644 --- a/src/mame/drivers/einstein.cpp +++ b/src/mame/drivers/einstein.cpp @@ -464,6 +464,7 @@ ADDRESS_MAP_END /* The I/O ports are decoded into 8 blocks using address lines A3 to A7 */ static ADDRESS_MAP_START( einstein_io, AS_IO, 8, einstein_state ) + ADDRESS_MAP_UNMAP_HIGH /* block 0, ay8910 psg */ AM_RANGE(0x02, 0x02) AM_MIRROR(0xff04) AM_DEVREADWRITE(IC_I030, ay8910_device, data_r, address_w) AM_RANGE(0x03, 0x03) AM_MIRROR(0xff04) AM_DEVWRITE(IC_I030, ay8910_device, data_w)