Quoted from rai:
I just tried to update my game but after I rebooted it says update required.
Did I need to unzip the code or do I need to update twice?
It was an empty USB stick.
I went through this updating my game last night. First USB drive I used had the same result as you (Update Required Screen - even tried it 3 times) Found a different drive and repeated the process successfully - so it appears that the system is rather picky on the media used.
Only issue I had other than that was my settings and scores all reverted to factory defaults - realized that on the first game I played on the new code and started hearing beeps...