It's probably not the D0 - if it works in the first place, your D0 is right. The D0 is basically what tells the xbox to look for the chip.
I know this has been discussed before, but I can't really remember much about it. Hopefully someone will have a better solution. In the meantime, the only thing I could suggest would be to check your other solder points, make sure everything is connected properly. Not sure if that's it or not, but couldn't hurt to check.