I recently downgraded my iphone 2g from the 2.0 software to the 1.1.4 software. I had a bit of trouble but after using several different programs I managed to do it.

After unlocking it I tested my contract sim in the phone, which I currently have in my new iphone 3g and it worked fine, but when I try it with any other sim I cannot make or receive calls and the carrier option is missing from the settings.

I was hoping to sell my 2g phone on to make up for the money I spent on the 3g upgrade, but if I cannot solve this issue then no one will buy it off me. Does anyone have any ideas about what this might be? It seems like a slightly different problem to other carrier issues because it works perfectly with my original contract sim! I have checked several times and the unlocking process was successful with both ziphone and iliberty+ so why does only my original sim work? I don't understand!

Any help or ideas would be appreciated, Cheers.