Okay, this is what you do:
1. connect D0 to ground without chameleon. If it frags (xbox turns on&off then flashes diff. color), your D0 has good connection.
2. use a voltmeter to determine if all your LPC points have teh correct voltage. Compare it to the LPC diagnostics tutorial. Make sure they're good, before AND after you put in the pin header. Yes, the pin header is the best way to go. :-)
3. If 1 & 2 are okay, connect your mod and the D0 wire. If it frags, then you either have no bios in that particular bank or its bad. Switch around the banks to see if they work. also, make sure u're in mode 1. OR it could mean that your xbox is v1.5. The LPC tutorial can help you differenciate between v 1.4 and 1.5.
4. If you have a v1.5, solder in 3.3 volt and ground? I'm not too sure about this because I've never had to mod v1.5 before.
hope this helps. :-)