While we have various methods to carrier unlock Apple’s iPhone available, all of them share issues such as the phone being re-locked after a firmware update. Negri Elelectronics brings us a new method, remotely unlocking after receiving your iPhone’s IMEI code, which is permanent and lasts through firmware updates and other software modifications.
Negri Electronics’ unlock service runs $175 and requires a two-step process: purchasing the unlock, and sending in your IMEI which gets added to a database. Presumably Apple would not close this unlocking method in the future as it is the “official” way to remove a subsidy lock – if AT&T offered the carrier unlock, it would be delivered the same way.
Source: Negri Electronics