I've got a 3G (3.1.2) that is JB and unlocked. It's originally a Spanish iPhone, I'm using it with a UK SIM and don't have the Spanish SIM. I also am a bit of an unlock idiot, thus the question. Can I restore this phone? Or will that restore it to its unjailbroken state? If so... what should I do before selling the phone on? Cheers for any pointers.