Unlocked Iphone with AT&T

[x-ception]

I have an unlocked 8gb Iphone with 1.02 firmware on it. I want to use it with At&t now and i have at&t service. Do I need to upgrade to the new 1.1.1 firmware? If so what would be the procedure to use my existing at&t sim with the iphone?

Thanks for your help.

[CJ Majesty]

So The phone has to be unlocked to use a different AT&T sim card than the one it came with?

[x-ception]

Help Anyone?

[xcuter]

Im in the same boat as you. I just bought an iphone with 1.0.2 and its locked. I want know what i got to do to use t with my old att sim card. I do not want to sign up for another 2 years and i do not need the data plan.

[stewsan]

Not sure if this will help, but when I go to the USA, I put in my old att sim card which I still keep an account on, hook up to "INdependence" and activate it. I still have the 1.0.2 in my unlocked iphone.