Guys i need some help asap! Firmware 2.2 question

[bunnywhi7e]

Hi.

I'm on AT&T with iPhone 3G 8gb and I recently updated my firmware to 2.2. I'd like to end my AT&T contract and go with T-Mobile and use the sim adaptor that I already have ready to go. All I need is a T-Mo service and the sim card. Now, is it true that these sim adapters don't work on 2.2 firmware. If they don't, is there a way I can go back to 2.1 ??

[Rip]

There was a post today on Everythingicafe from someone in Thailand who had gotten his to work with 2.2.

[Poseidon79]

As of right now there is no possible way to downgrade back to the 2.1 firmware's baseband. You will either have to buy a new SIM chip after one comes out or contact the manufacturer of yours and see if there's a way to upgrade it with a SIM read/writer.