I have a laptop and a home computer. I'm at college but I recently bought a new 4G to replace my 2G but before doing so, I made a backup on iTunes of my 2G. I didn't sync, I just backed it up. So when I restore the backup on my new 4G, everything's fine, but when I tried syncing to my laptop, it said it needed to erase everything. And of course I didn't want to, I spent an hour getting all my jailbreak stuff in order. Does this mean I have to go home and sync? And does this mean when you restore backup from another iPod that the iPod you're restoring to retains the same home/original sync computer?