So, i purchased a 'used' iPhone from a reseller- just barely out of warranty, and i would assume locked. the model number is MC318LL on 04.10.01 bb and 4.3.4 (8k2) ios. When i first got it, and i stuck in an ATT sim, it worked. When i stuck in any others, it showed one bar but no carrier logo. This made me think it was a locked version. When i connected to itunes (with wrong sim) it asked if i wanted to activate. I cancelled, and then it stated that there was an error activating. I then shut it down, switched to ATT sim, and reconnected. It asked me again if i want to activate, i said yes. It then promptly tells me "congrats (or something to that effect) your iPhone is now unlocked". i switched the sim to the third party sim and voila! it works. the Carrier originally stated ATT carrier 10.0, now it just stets carrier 10.0 So. does that mean my iPhone 4 is a factory unlocked version? meaning i can update the iOS and baseband to current and it'll stay unlocked? or was this some funky thing that some users experienced when they activated their att iPhone with a diff. sim card at home?? cheers all!