Hey guys,
I'm not up to speed on the iPhone jailbreaking/unlocking, someone on here might know the current situation. I used to have a 2G iPhone (original, US import), which I unlocked and gave to my sister after she dropped her 3G iphone, now she's just tried to restore it (presumably to the latest firmware, 3.1.3), even though I told her to absolutely not do it
Now it's not accepting the SIM (O2 iPhone contract), even though this is an american iPhone I would have thought this should still work? 
Any of you guys know if this should work? If not, is this firmware unlockable? I'm having trouble getting a straight answer out of google.
I'm not up to speed on the iPhone jailbreaking/unlocking, someone on here might know the current situation. I used to have a 2G iPhone (original, US import), which I unlocked and gave to my sister after she dropped her 3G iphone, now she's just tried to restore it (presumably to the latest firmware, 3.1.3), even though I told her to absolutely not do it


Any of you guys know if this should work? If not, is this firmware unlockable? I'm having trouble getting a straight answer out of google.