new to iphone...question with unlocking without sim

[lunercrab]

ok so i'm buying my first iphone tonight used locally...i currently have tmobile so i need to unlock the phone...i've been reading up on jailbreaking/unlocking so i'm pretty much understanding the whole process...my question is, i'm not sure if the guy i'm buying from has updated his phone to 2.2, so if i need to update it via itunes, will i need an att sim card to do so? and if it is already running 2.2, will i still need an att sim card to jailbreak it and then unlock it? cause i don't have access to an att sim card, so i'm hoping i don't need one to unlock it...and if i do, can i just buy a prepaid one or something? thanks guys...sorry i tried searching, but couldn't find a definative answer...😱

 

[Moi un Mouton]

If it's not on 2.2, you don't need an AT&T sim to get there, put your T-Mobile SIM in it, connect and put it into restore mode. Then restore to the 2.2 firmware. You'll find links to that here: http://www.iclarified.com/entry/index.php?enid=750