Good Luck, I have an xbox with the wrong hdd, it was a bad relocking of the drive, now I cant get it to unlock at all, even with the computer and the eeprom. Unfortunatly most original xbox modchips are hard to find. There is a guy working on an x3 replacement currently, dont know the status of it, he was posting about it here, after not being able to find exactly what you are looking for. He had videos with promising results, but was still working on his custom OS for it.

Search the forums, it is here somewhere.