While AT&T had recently revised its unlocking policies for smartphone to now include Apple’s iPhone, the carrier’s policy makes it expensive to unlock Apple’s most recent flagship, the iPhone 4S, requiring either users upgrade their device, purchase their devices out right, or pay an early termination fee. Fortunately, there are hackers and enterprising users who have found ways to unlock the iPhone 4S, though with methods that may not be approved by Apple. The method does require a jailbroken iPhone and will work on the iPhone 4S, though with the iPhone 4S, to jailbreak, you’ll have to run iOS 5.0.1 or earlier as there is no jailbreak yet for iOS 5.1.
Users who attempt to SIM unlock their iPhone smartphones are also advised to have the latest version of Apple’s iTunes software for their Mac or PC computers.
According to Gizmodo, here are the steps to unlock your device:
Go to Cydia and add repo.bingner.com as one of your app repositories. Search for Sam Bingner’s SAM package and install it.
Click on SAMPrefs icon.
Go to utilities. Select De-Activate iPhone. Make sure your iPhone is deactivated under More Information.
Click on By Country and Carrier in Method. Then select your carrier.
Click on More Information again. Copy your IMSI (International Mobile Subscriber Identity) inSAM Details.
Click on Spoof Real SIM to SAM.
Go to the main SAM menu and change the Method to manual. Paste the IMSI in the field.
Connect the iPhone to iTunes. It will reactivate your iPhone.
Disconnect your iPhone when done and quit iTunes.
Disable SAM in the SAMPrefs app.
Connect your iPhone to the computer. iTunes will start up and tell you it can’t activate the iPhone.
Close iTunes and open it again.
This time, iTunes will activate your iPhone and it will be unlocked! You will be able to turn off your phone and do whatever you want. The unlock will keep working, at least until Apple releases its usual countermeasures in a firmware update.
If your push notifications stop working, go to SAM again and click on Clear Push then connect to iTunes again.
U.S. iPhone users who unlock their iPhone can now use their phones on T-Mobile USA network. In select geographies in the U.S., T-Mobile will allow customers to use their iPhone devices on 3G whereas before, unlocked iPhones could only operate on 2G EDGE model on T-Mobile USA. This new change is due to T-Mobile turning on compatible spectrum that will work with the iPhone.
In addition to using the phone on a rival domestic carrier, many users may want to unlock their iPhones for traveling to international destination. This way, they can use a prepaid local SIM card rather than pay high roaming charges to their carrier at home.
Users who do not want to jailbreak also have another option–to purchase an unlocked, unsubsidized iPhone directly from Apple.