diff --git a/src/mame/machine/inder_vid.c b/src/mame/machine/inder_vid.c
index 3d4950c2d75..3a68cb6884d 100644
--- a/src/mame/machine/inder_vid.c
+++ b/src/mame/machine/inder_vid.c
@@ -28,9 +28,8 @@ static ADDRESS_MAP_START( megaphx_tms_map, AS_PROGRAM, 16, inder_vid_device )
 	AM_RANGE(0x04000010, 0x0400001f) AM_DEVREADWRITE8("ramdac",ramdac_device,pal_r,pal_w,0x00ff)
 	AM_RANGE(0x04000030, 0x0400003f) AM_DEVWRITE8("ramdac",ramdac_device,index_r_w,0x00ff)
 	AM_RANGE(0x04000090, 0x0400009f) AM_WRITENOP
-
+	AM_RANGE(0x7fc00000, 0x7fffffff) AM_RAM AM_MIRROR(0x80000000)
 	AM_RANGE(0xc0000000, 0xc00001ff) AM_DEVREADWRITE("tms", tms34010_device, io_register_r, io_register_w)
-	AM_RANGE(0xffc00000, 0xffffffff) AM_RAM
 ADDRESS_MAP_END