Error 21 and 1600

I recently had a crack at jail breaking my ATV2. It was successful and I was using XBMC however it locked up during the process and I unpluged the ATV to restart it. When going back into XBMC it failed to open every time.

I returned to restore the ATV to original settings before trying the seas0n pass again. I now either have a error 21 or error 1600 sometimes it wont go into DFU mode.

What should I do?

Thanks,

Jake.