I did a bit of Mroogle searches but I couldn't come up with the answers I'm looking for. Here's my situation: A friend of mine received an unlocked 3GS from her cousin last night. She is using it with T-mobile. This morning she synced with iTunes, and accidentally updated to 3.1.3. I suppose you can see where this is going... Since I am a bit more (way more) tech savvy than her, the task of getting it to work again is now placed in my hands. In order to make this work, I'm assuming the following steps need to occur: 1. I need an AT&T SIM card so I can do a restore in iTunes. Right now when you connect it to iTunes, all I see is the invalid SIM error screen. This is no issue as my brother is mailing me an unused AT&T SIM card from his old iPhone, which is no longer in service. 2. I'll need to downgrade from 3.1.3 to 3.1.2. I read a guide that describes this process as being a bit more difficult than in the past but it's nothing I won't be able to do. 3. Jailbreak with the unused AT&T SIM using the Spirit Jailbreak tool. 4. Unlock using whatever software is needed. I'm running 10.6.3. Does this sound logical?