Steve This is for you dude!
1) Download a good hacked bios from the usual sources. I suggest the X24983
2) FLASH ONLY one of the two banks!
That way if you mess it up you can reboot to cromwell and try again. Here's how:
3) FIRE UP X2BE.
Choose 512k bios. Yes, 512k, not 1mb! Fill in the first two banks with your X2 hacked bios that you downloaded. Then save the results as bios.bin (the default file.)
4) BURN IT.
Get Nero and a blank CDRW. Take a 100mb random file on your HDD. Rename it to 0dummy.bin. Add this file and your bios.bin file to your compilation. Burn at 2x, DAO/96, FINISH CD. This is your BIOS CD.
5) FLASH IT.
Turn off your XBOX. Set the external switches to "ENABLED, BANK 2, UNPROTECTED." Turn it on and get cromwell. When it prompts, drop in your newly minted bios CD. Wait for it to do its thing. When its done, it will turn off the XBOX.
6) USE IT.
With the power still off, set the external switches to "ENABLED, BANK 1, PROTECTED." Say a quick prayer and turn on your XBOX. You should get a flubber with the Xecutor 2 message. You are done!
IF YOU EVER NEED TO REFLASH, just set the external switches, with the power off, to "ENABLED, BANK 2, UNPROTECTED" . Then turn on your XBOX. It should boot into Cromwell and you can then reflash your bios.
Credit goes to U2mir!!