Hi everyone, I've had O2 officially unlock my iPhone but it keeps locking everytime I turn it off and on / deactivate and activate the flight mode with a foreign SIM card. When I connect the phone to iTunes, the activation screen saying "your iPhone has been successfully unlocked - OK" comes up and the phone can be used again. Restoring didn't help. I recently had this phone swapped and the one before, also officially unlocked, never had this problem. Help, please?