Iphone 3gs upgrading question

[wdowell84]

First of all, I'm new to the forums, so I just wanted to say hi. Next I have a question.

I have an iphone 3g on 3.0 firmware that has been jailbroken and unlocked and is currently using T-Mobile as the carrier. I wanted to give this phone to my younger brother in law, since I'm going to be upgrading to the 3gs. However I want to have the 3g still jailbroken and unlocked but all of my personal information taken off.

Am I right in thinking that I can backup my settings on the 3g and then restore it, and just rejailbreak and unlock it again? Or would it make me update the firmware to 3.1.3 which has a problem with unlocking right now. Also if I saved my backup settings on iTunes then can I use those when I get the new 3gs model and just transfer them over? Then I would just have to jailbreak the 3gs because I don't want it unlocked at this time.

Thanks for the help guys.

[mavrik101]

Download an activated custom firmware, NOT 3.1.3. It will wipe your phone, have cydia installed, and you can run ultrasn0w to unlock. I've done it dozens of times. My 3g is on 3.1.2, with baseband 04.26.08.
Custom firmware wont upgrade your baseband, so unlock will always be available.