IPhone 3G unjailbreaking help

[Ak47gunner]

Alright so heres my story. I bought an Iphone 3G from some guy off craigslist and he gave it to me in perfect condition, it was already jailbroken and unlocked which is perfect because im using it under tmobile. So now I have a lot of dust under the screen and some scratches on the back just regular wear. So i talked to a guy at apple today and i told him about the dust and he said to make an appointment bring it in and theyll probably give me a new one. I still have insurance on it which ends around the end of july. So i was thinking well ultra sn0w is coming out soon right, and im going to uprgade my jailbreak and unlock to 3.0 soon. But to take it to apple i cant take it jailbroken and unlocked so what do it do to ujailbreak it and leave no trace of it ever being jailbroke? and will they want an att sim card in it? Do i need some id from the guy i bought it from? should i just tell them i bought it from someone and will they just see the dust and give me a new one? so someone please help me! sorry theres so many questions...

 

[Ak47gunner]

Oh also i will be jailbreakin the new one i hopefully get to 3.0

 

[eshiku]

just restore the phone on your itune (upgrade) once you do that, they wont know that you have ever jailbroken it.

for the sim card part, is best if you can bring a ATT sim card with you. sometime they will ask for it, and maybe will not ask. if you get a nice genius, they might exchange it for you even if you dont have a ATT sim.