Lately my jailbroken and unlocked first gen has been dropping calls and generally having really poor reception. A lot of the times it just reads no service until I turn the antenna on and off. It is FW 1.1.4 and all the unlocking was done using iJailBreak on mac. I wanted to take it in for warranty repair/replacement but I don't know the proper restoring procedure. I restored with iTunes to 2.0.2. Is this sufficient or will Apple still be able to tell it was unlocked? Also do I need to take it in with a SIM card, because I don't have an AT&T one. The phone is in good cosmetic condition and has not been dropped or anything. Any tips appreciated.