There is one thing you can try. Updating the Flotilla firmware. If you want to give that a go, I can write up instructions ( or possibly a magic updater script ) for you to try; I wont publish them publicly yet though since I don't want anyone else to try it ( yet ).
Honestly, though, if it's not the cable then it sounds like you might have a marginal USB port that worked long enough to pass our testing and then failed. It's definitely possible!