Restoring to go back to Apple Store?

[myk13]

Ok here is the situation i am in. I have an unlocked, jailbroken original iPhone. I got it at launch date, i now have updated 2.0.1 on it using the pwnage tool. Whenever i turn my phone off it automatically turns itself back on. I am using T-Mobile btw. My girlfriend has AT&T but no iPhone and her brother has AT&T with an iPhone. Can i put their sim card in my iPhone and restore it thru iTunes? If so which one should i use, would it even work? The reason i ask is because i want to go down to the Apple Store by my place and see if they can take a look at it and possibly give me a refurb. Can they even tell if has been hacked if i restore thru iTunes? Do i run any potential risk of bricking it? What is the best way to get a "Genius" to look at my phone?

Thanks for any help, advice and responses.

 

[stevenmatyas]

if you restore it, it is back to factory settings, so they would not be able to tell. i know this because i have had to get my phone replaced a couple of times and i always restored right before and they never knew anything. the easiest way to get a genius to look at your phone is to make an appointment. you can do it online or set one up in-store.

 

[myk13]

but what do i do about a sim card? Since i have t-mobile i would have to use an AT&T card correct? Which one out of what i listed earlier would be the better option.