A method has been uncovered that unlocks the GSM iPhone 4S for T-Mobile. By taking advantage of an alleged bug in iOS 5, you can supposedly unlock your iPhone 4S on AT&T without jailbreaking.
To perform the hack, you’ll need a T-Mobile Micro SIM and your AT&T SIM from your iPhone 4S.
- Insert original carrier AT&T SIM card
- Dial 611 for AT&T customer service hotline and drop the call
- Turn on Airplane Mode
- Take out AT&T SIM card
- Insert T-Mobile SIM card
- Make sure WiFi is off ( also tap on ‘Forget this Network” to make sure it doesn’t connect automatically later)
- Switch off Airplane Mode and iPhone will search for network. This is followed by the Apple splash screen appearing.
- Activation Required will be displayed on the screen
- EDGE network will activate automatically – notice the ‘E’ on the top left corner of the screen
- Wait for about 20-30 seconds and turn off the phone
- Turn on iPhone and the same Activation Required screen will be displayed
- When you see one signal bar, tap on Use Cellular Connection
- Eject SIM card
- Activation Required screen will be displayed the second time
- Insert SIM card
While this workaround has not been definitively proven to work, many seem to think that following these steps will actually unlock the 4S.
Here’s danielscaleb’s success story:
After a little playing around, I confirmed that a certain iOS 5 bug leads to an unlock. Note, this will only work on GSM models. I’m going to figure out CDMA models next. Basically, you’ll need a GSM iPhone 4S, an AT&T SIM card, and a T-Mobile Micro SIM. Also, you could actually mess up your cellular radio doing this, though its very unlikely.
While this workaround seems like a hit or miss, it also seems to have worked for many people.
Apple sells the GSM iPhone 4S unlocked in the US for the full retail starting price of $649. Keep in mind that, although unlocking does free you from AT&T’s clutches, the iPhone can only use T-Mobile’s slower EDGE network in the US.
Update: It appears that this unlock may only be temporary. According to MuscleNerd, unlock expert for the iPhone Dev Team: “Unfortunately it’ll just relock again once a new TMSI is required (various normal network operations require TMSI refresh)”