Unlock Your iPhone 1.1.2 (To Use a Non-AT&T Provider Like T-Mobile)

Update: There is a new application called ZiPhone which provides a simple way to jailbreak and unlock any 1.x.x firmware version. Check it out!

First, jailbreak your iPhone or iPod Touch. You need a jailbroken iPhone or iPod Touch, with 1.1.1 or 1.1.2 firmware, before you can unlock it for use with a cell provider other than AT&T. These instructions will not work with a 1.1.3 otb iPhone.

Software Unlock Your iPhone (1.1.2 otb Not Supported)

If you are lucky and have an iPhone that has a firmware version out the box (otb) older than 1.1.2, you can software unlock it to allow the use of non-AT&T cell providers such as T-Mobile. Follow these steps to software unlock your iPhone:

1. Disable the Auto-Lock (to prevent the iPhone from sleeping) by pressing the home button and tapping on Settings->General->Auto-Lock->Never.
2. Press home button and tap the Installer icon. Update the installer if necessary.
3. Tap the Install tab, scroll to the System category, and install the BSD Subsystem.
4. Go back to the Categories list by tapping the Install tab, scroll to Utilities category, and install anySIM 1.2.1u for your jailbroken 1.1.2 iPhone. Install anySIM instead if you have a jailbroken 1.1.1 iPhone.
5. Turn airplane mode on by pressing home button, tapping on Settings icon, finding Airplane mode, clicking on the OFF button. The button should slide to the left, get colored, and show ON.
6. Press the Home button and tap on the anySIM icon.
7. anySIM will run and tell you if it is successful (your iPhone will need to reboot). You may get an error message; for example, if you try anySIM on an iPhone 1.1.2 otb (it’s okay if this happened, nothing is permanently damaged).
8. If anySIM succeeded, replace the original SIM card in the iPhone with your T-mobile (or other) SIM card. The SIM card is located at the top of the iPhone; just firmly insert a pin or paperclip into the hole and it will pop out. You can leave the iPhone running while you swap the SIM cards.
9. Cross your fingers and if the iPhone doesn’t complain about the SIM card, then you are in business.
10. Turn airplane mode off by pressing home button, tapping on Settings icon, finding Airplane mode, clicking on the ON button. The button should slide to the left, grey out, and show OFF.
11. Check the cell and signal info in the topmost-left corner. If you get a signal, congratulations, you have an unlocked iPhone!
12. If you have disable the Auto-Lock, don’t forget to re-enable it by going to Settings->General->Auto-Lock. The default is one minute.

Undo the Software Unlock (Only 1.1.1 iPhone)

In the future, if you wish to go back to the original Apple firmware or wish to deliver your iPhone to Apple for service, it is recommended that you undo the unlock (lock the iPhone back to AT&T only) and undo the jailbreak first. Note that the following instructions to remove the unlock will only work for jailbroken 1.1.1 iPhone. To undo the unlock, do the following:

1. Replace your T-Mobile (or other) SIM card in the iPhone with the original AT&T SIM card.
2. Press home button and tap the Installer icon.
3. Select Sources tab, click on Edit, then Add button.
4. Input i.unlock.no and hit OK button.
5. The Installer will refresh its sources. Hit Done button.
6. Tap the Install tab, scroll to the Unlocking Tools category, and install OneSIM for your jailbroken 1.1.1 iPhone.
7. Turn airplane mode on by pressing home button, tapping on Settings icon, finding Airplane mode, clicking on the OFF button.
8. Press the Home button and tap on the OneSIM icon.
9. OneSIM will run and tell you if it is successful (your iPhone will need to reboot). You may get an error message; for example, if you try oneSIM on an iPhone which has not been unlocked with anySIM.
10. Turn airplane mode off by pressing home button, tapping on Settings icon, finding Airplane mode, clicking on the ON button.

Follow instructions at the end of jailbreak your iPhone or iPod Touch to undo the jailbreak.

Hardware Unlock Your iPhone (1.1.2 otb)

If you have an iPhone 1.1.2 otb, you will need to get a hardware hack like i3gSIM, stealthSIM, or turboSIM (all of them cost about $70 each). They are thin covers that go on top of your T-Mobile (or other) SIM card; you will need to cut out part of your SIM card to accommodate part of the cover (the part you cut is just plastic and harmless to remove). I’ve tried i3gSIM on an iPhone 1.1.2 otb and it works!

Note: These hardware SIM hacks do not work with otb 1.1.3 iPhone.

The information above was derived from the website Unlock the iPhone.