i survey the C51 user's guide about code bank switch and followed step sequentially. the main problem i wonder is that at options at code BANK just had "common are, bank #0~3",is any option else, ex: "bnak #4,bnak #5,bnak #6...", for choosing???
Are you sure that you are looking in the dialog Project - Options - Target? If so, send a screen shot to support.intl@keil.com