My friend wants me to upgrade his ipod to ios 4.0 beause he doesnt have a comp. I tried to transfer all his stuff and it was backing up, but then i unplugged it cause it was taking too long. It turns out some of his songs on his playlist list was deleted. so my questions are, 1. What are is the correct way to do this, and if i was doing it correctly, why did it get rid of some of his songs 2. for upgrading to ios 4.0, do i have to backup or can i just upgrade?