Originally Posted by iphonewarrior
Just update your iphone through iTunes. It's totally different to Restoring, you wont need to re-sync your stuff back on.
I'm doing that as I type right now however I'm considering restoring it again.
I had updated to 3.1 and was getting terrible battery life and horrible signal performance none of which I experienced before the 3.1 upgrade from 3.0.1.
So I restored 3.1 yesterday and the battery life was excellent yesterday as well as the signal strength, texts no longer took a couple minutes to send etc...
So now I just upgraded to 3.1.2 and I'm thinking I should restore it just for good measure, sure it's a PITA but it ensures the purest form of install so nothing can possibly be messed up.