[billpaetzke]

I heard there was a difference between factory unlocked phones and phones unlocked some time later (let's call them store unlocked phones). Such that the factory unlocked would retain the unlock if you wiped/reset the phone (for instance, to sell it to someone else), but the store unlocked phone would need to be re-unlocked (because its factory settings are of being locked).

If someone could back me up or refute this, go ahead. For me, I just buy the factory-unlocked phone straight from apple.com and don't have to deal with it. (I go out of the country enough that it's worth it to me).

[ben1040]

There should be no difference. "Out of the box" and after a reset, the phone is a blank slate and won't work until it talks to Apple.

Part of that activation process involves getting a token back that instructs the phone how it should be locked, or not at all.

The unlock process that AT&T (and every other iPhone carrier) does is that they instruct Apple to update the record on their activation server to say your phone should be getting a "fully unlocked" response. Next time you tether the phone to iTunes it checks the activation token and unlocks the phone.

[bshep]

AFAIK the lock( or unlock ) status is stored in a special area of the baseband and should survive updates/restores.

The best people to answer this is probably someone from the Dev-Team.

[watmough]

I believe the phone phones home to Apple to verify its unlock status, and this is only known for the store unlocked ones.

Hence the 'Successfully unlocked' message when you restore an unlocked phone.

[joshmlewis]

There's a difference between being unlocked through normal processes and being unlocked with a special sim or jailbrake/unlock.