Try flashing to BigJ's ROM first. Here is the link
http://ppcgeeks.com/bigjs-hybrid-1-2...-07-t6876.html
Then try restoring your backup with Sprite.
I think the problem is trying to write over and OEM ROM with a Kitchen ROM, so if you install BigJ's ROM you will be going from a Kitchen ROM to a Kitchen ROM which should work better with Sprite.
__________________
1. Read the FAQs, Stickies, Wiki
2. Do a SEARCH!
3. Be Very Specific
4. Give THANKS to those who deserve it!