Ernegien

Sounds like an install issue. I'd do a good sweep of the board for stray solder (or conductive pieces) and make sure there aren't any unwanted bridges. I've highlighted one area of interest. It's possible you've already damaged something if any of the bridges (now or previous) dealt with a power rail.

This might interest those that want to turn their retail/debug Xbox into a fully-functioning development kit without having to spend $500+ on one. It works on any version 1.0 through 1.2 motherboard and can be great for troubleshooting crashes of all kinds without requiring the use of XDK software. I'm selling pre-made units for $30 plus shipping and would also like to get a feel for how many might want one in Europe so I can bulk-ship to a distributor to help save some on shipping costs as it's usually around $15 USD to ship from the US otherwise. Everything is fully open-source if you'd like to build/sell them yourself as well. Any questions, feel free to ask. https://github.com/XboxDev/serial-usb-adapter