If you want to restore using someone else's rom backup, you would need to remove the encryption first. Hfade posted a tool a while ago which lets you do just that. You can download it here:
AximUpdate.zip
Then you would have to run ris2ris0 on your friend's rom backup and use the restore utility from dell to restore the hacked .ris file.
The .zip file above also contains a hacked aximupdate.exe file that let's you continue with the English rom update irregardless of the PDA's initial language. Use this only if you want to change from any other language to English and don't have your friend's rom backup, otherwise use the previous method. I tried this only on an X50v, so use it at your own discretion for any other models.
This was originally posted by hfade here:
http://bbs.pdafans.com/viewthread.ph...light=%2Bhfade (chinese)
http://www.aximsite.com/boards/showthread.php?t=76975