Upgrading an activated iPhone
I just received my iPhone today which I purchased from ebay. Its previous owner has activated it somehow so that it functions as an iPod/Wifi etc with the AT&T simcard inserted, but it's not working for any phone functions of course. The software version is still 1.00. I'm not sure if it's still jailbroken or whether it was returned to jail.
My question is, if I want to upgrade the software then is there anything I need to look out for? Do I need to do some sort of checks to make sure that it isn't still "jailbroken" before applying an update from itunes? I don't mind having to activate it again afterwards (it doesn't really have any personal stuff in it yet so I don't even care if it loses all my data).
Any advice on how to proceed from people with more experience?