Hi,
I have the white duo x2 gs cromwell (2 banks 512k) by AMD.
It's been working for a while but i just discovered that bank 2 doesnt have any BIOS (the xbox boot but nothing on the screen), some people said me to flash with flashbios 3.0.3 but i don't have any cd-r plus one of my friends wasn't able to flash with this program and was stuck with it...
All i have is Dvd-r and the xbox is connected to my switch.
In overall info:
White AMD duo x2 GS
Xbox V1.6

couldnt you just flash the bios with slayers auto installer disc?
dont just go and download slayers as i know you can flash with it,just wait and see what other people with more knowhow about this say.

Bank 1 (bank 0 is the first bank) will have flashbios on it. But you have a 1.6B most likely and the blank screen bug in flashbios is the reason you have the issue with that bank.
You can boot from bank 0 stick in AID or Slayers then flick the switch to bank 1 and flash over the bank that is giving you the blank screen.

Dont bother with flashbios and all that rubbish, follow this guide and just flash it in evox

http://www.xbox-scene.com/articles/flash-modchip-evox.php

After wards ftp the bios files u want to flash to C:\bios\

Just do as Chancer said and flash with AID or Slayer's.
If you don't wanna mess with discs at all, then get a program from the usual places called FlashX.
You can FTP flashX (and your BIOS) to the console and reflash directly from there without need for discs.

Plenty of choices if you wanna reflash it.

. . . but since you already have a working BIOS on your chip, there's no need to reflash anyway.