I've run a few different RUU's multiple times, and they either give me a signature error or the update starts and freezes 98% thru writing the radio. If I try to write anything in flashboot, it will accept the files, but again all the writes fail.
I have a goldcard in the phone as well, using the file I created a few months ago to root the phone. Perhaps I need to redo the goldcard and try that route. Also, while RUU and flashboot both see the phone, ADB never seems to.