I've had a Matrix installed in my Xbox since last November, and even though I've had to reposition it time and time again (seems to be fixed since I filed down the pinheader and put a little electrical tape around D0 to stop it from touching anything else) it's performed pretty well.
About a month ago when I try to power on my Xbox with the matrix active, it sounds like it's trying to boot, but the light doesn't come on. I can hear the 80gb WD hdd spin up a couple times, before the big LED starts to flash red. Nothing comes on screen at all.
Now, the strange thing is that this is solved by simply unplugging my High-Def pack, then plugging it back in. The Xbox then boots flawlessly, with no problems otherwise. Anyone have any idea what it could be? When I remove the chip, for whatever reason it boots fine and to the MS dash every time.