Nu trebuie jailbreak, se pare ca are iOS 5 un bug.
http://osxdaily.com/2011/11/17/unlock-the-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
Unlocked!
.