How to unlock iPhone 4S to work with T-Mobile without Jailbreaking

There is a bug that will let you unlock the iPhone 4S without jailbreaking it.  The bug was discovered by Michael Capozzi. He unlocked his iPhone 4S to use it on T-Mobile. I tested it out and it does work. Keep in mind this is temporary.  You will also have to cut the T-Mobile SIM card to micro-SIM card size for it to fit iPhone 4S’s SIM tray. MuscleNerd of the iPhone Dev team states:  “it’ll just relock again once a new TMSI is required various normal network operations require TMSI refresh. If you are successful at temporarily gaining network access, you’ll lose it as soon as TMSI is refreshed (happens often). The TMSI refresh is a normal, regular action on the network (it’s actually intended to protect you).”  If  you still want to try it here is the video and the steps to do it yourself.

1. Put in your original carrier AT&T SIM card
2. Dial 611 for AT&T customer service hotline.
3. End the call
4. Turn on Airplane Mode
5. Take out your AT&T SIM card
6. Put in your T-Mobile SIM card (It has to be cut to fit your iPhone 4S)
7. Turn off WiFi  and make sure each one is set to Forget this Network.
8. Switch off Airplane Mode and iPhone will search for network. This is followed by the Apple splash screen appearing.
9. You will see an “activation required” on the screen
10. EDGE network will activate automatically
11. Give it 30 Seconds then turn off the phone
12. Turn on iPhone. You will see the same Activation Required screen as before
13. Click on Use Cellular Connection
14. Take out the T-Mobile SIM card
15. You will see the Activation Required again
16. Put back in your T-Mobile SIM card
17. You now have a iPhone 4S that is unlocked