Please help. I am so confused with so much info and which applies to me... Ok, I have iphone 3gs running 3.1.3(7e18) OS and 05.12.01 modem firmware. it is unlocked and jailbroken with DEVteam tool, dont remember which one. I want to update the OS to some version of 4.x. and have it jailbroken and unlocked since I am on T-mobile. does anyone know the safest way to get it done if there is one? thank you in advance. please don't bother to answer if all you have to say is that it is illegal, you can use iphone with att only and things like that. thanks again to all of you.