Is my iPhone unlocked?

[h4mza]

I have a new iPhone 3GS and i popped an O2 sim and it didn't come up with anything, so does that mean it does not work on O2 and it is network unlocked to some other network? iPhone hasn't been registered yet if that counts.

Im looking to sell it but is it possible for someone to register it then block it and ask me for refund?

 

[Interstella5555]

Where did you get it? Wouldn't they have told you the status of the phone?