Update iPhone?

Hello guys and gals,

I'm the owner of an unlocked (not jailbroken, since there's no Cydia or anything) iPhone (at least I think it's unlocked, I can insert any SIM-card I like, or even no card at all and it still works) and I'd like to update from 3.1 to 4.1 through iTunes.

Now I've heard that this might cause the phone to stop working. Is that correct? I'd really like to update, but then again I wouldn't wanna go through the hassle of having to reset it to default settings.

Thanks in advance,

Florian

 

Thanks for your reply. Is there any way to make sure it is factory-unlocked? I just want to make extra sure, just in case.

 

No, the only thing that was installed when I got it was the Nike+iPod app, but that seems to be pre-installed on every 3G S. It was a birthday present.