question about returning iphone to apple for new battery replacement?

[lunercrab]

Ok so i bought a 3g bout 6 months ago used...i have it jb and unlocked to use with tmobile...anyway my battery life is horrible, i have it fully charged and it's dead within like 5-6hours of mostly standby and a few 5 min or less phone calls...now i read about apples replacement battery program for like 80 bucks, but i have a few questions....if i take my phone to apple, do i get back the same phone or will they give me a replacement instead, even though the phone changed ownership, it's still technically under a year old and also will they update the firmware on me or do they give it back with the same fw i gave it too them with? i'm curious cause i'm unlocked with yellowsn0w, running on 2.2 fw so i can use it with tmobile..but i'm afraid they will wind up updating my phone with 2.2.1 and the higher baseband, which will leave me without a phone....anyone here know how the process goes?

[Poseidon79]

If you don't have a valid AT&T sim card to activate the new phone they won't warranty anything for you. You need to get a friend with an iPhone plan on AT&T to lend you his SIM card.