How to unlock your iPhone 4 or Iphone 3GS running on iOS 5.1.1 using UltraSn0w 1.2.7

Here we go again with another guide on unlocking your iPhone 4 or iPhone 3GS running on iOS 5.1.1. This is the latest and most stable way of unlocking the 5.1.1 firmware and we thoroughly recommend you using this one instead of the previous temporary one, which was essentially a hacked up version of Ultrasn0w. Using the tutorial below you will do a proper unlock and you”ll avoid any bugs that may occur due to unstable unlocking tools. So relax, read carefully and follow all the steps and if you need any specific help feel free to comment and you’ll receive a reply from one of our writers as soon as possible.

To unlock a phone means to remove it’s carrier restriction. Unlocking is technically reversible so you don’t have to worry about voiding your warranty too much. If your phones start acting weird you can restore it through iTunes and send it to be repaired, but only if you actually can restore it, that is, if it works to the point that it can be restored. Legally, you can unlock your phone, it is not protected under the DMCA agreement but it can void your warranty if the seller finds out. Also important to note is the fact that some carriers have no problem with unlocking, to be sure just call them and ask. Some even unlock the phones themselves for a fee.

Please take note that the following unlock work only on these basebands:

• iPhone 4: 01.59.00
• iPhone 3GS: 04.26.08, 05.11.07, 05.12.01, 05.13.04, and 06.15.00

To check the version of your baseband please go to Settings -> General – > About and look for the field entitled Modem Firmware as show in the photo below.

 

Note: In order to unlock your iPhone 4 on the iOS 5.1.1 firmware then you must first have to update to iOS 5 through a custom IPSW created using RedSn0w 0.9.9b5. Caution:  Do not update the to the stock  iOS5 as this will also update your baseband.

Note: While this is not mandatory or required it would be good if you can sync and backup your iPhone with iTunes to make sure you’ll save all your important data (photos, music, documents, settings and contacts)

Step 1.  Firstly, your phone must be Jailbroken in order to do this. You can use one of our simple guides to do so.

Step 2.  After your iPhone has been jailbroken go ahead and launch Cydia.

Step 3.  Do a search for ultrasn0w 1.2.7. If you find it there then proceed to step 6, If not then you have to add it manually. But don’t fear because this is really easy to do. Proceed to step 4.

Step 4.  In order to add Ultrasn0w to Cydia you have to add its repository link. A repository is kind of like a server which stores apps that can be accessed remotely through special apps, like Cydia. To add the repository you have to go to Manage then tap Sources.

Step 5. Then you press Edit and then Add. After this write down the following repository URL http://repo666.ultrasn0w.com

Step 6. Now we have to install Ultrasn0w 1.2.7 by clicking install and then confirm

 

Step 5. Wait patiently until  UltraSn0w is installed then restart your iPhone and you’re done.

Enjoy using it with your favourite carrier!