I don't know alot about chips, but if you have a disc to flash your bios, then try this. All you need to buy is a molex power splitter, which should only be $2-5 US.
1. Remove the cover of your xbox
2. Remove the PC-CD Drive from your computer.
3. Attach the molex power splitter to the power cable on your XBOX HDD
4. Plug the splitter into the PC-CD Drive and the XBOX HDD
5. Unplug the IDE cable from your stock DVD-Rom on your XBOX and plug it into the PC-CD Drive
6. Make sure that there is a disc in and the yellow power cable is plugged in on your XBOX DVD-Rom
7. Put your disc for flashing your Bios in the PC-CD Drive
If you do this then your XBOX will be able to read a cd-r or -rw
And If you don't want to spend the money for a molex splitter, you can leave the power cable connected to the PC-CD Drive from the computer and just plug the IDE cable into it with you're computer running (but it probably won't be long enough).
Sorry but I'm in the middle of a 12hr night shift and I'm exhausted. Reply to tell me how it works!!