Ultrasn0w 1.2.4 iPhone 4, iPhone 3GS iOS 5 Firmware Unlock How To Guide

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Rejoice if you have been waiting for iPhone 4, iPhone 3GS iOS 5 firmware unlock as the iPhone Dev Team has released ultrasn0w 1.2.4 with iOS 5 compatibility fix. Using this new ultrasn0w update, you can unlock your iPhone 4 on baseband 01.59.00 and iPhone 3GS on basebands 04.26.08, 05.11.07, 05.12.01, 05.13.04 and 06.15.00.

For those who don't know, ultrasn0w gives you what is commonly referred to as a software unlock for iPhone. If your iPhone 4 or iPhone 3GS is on any of the basebands mentioned above, you can easily get an iOS 5 unlock. By unlocking your iPhone, you will be able to use it on any carrier in the world as well as the one from which you bought it. For example if you bought your iPhone from AT&T with a two-year contract, you can unlock your iPhone to use it with any carrier of your choice as well as AT&T. If you currently own a previously software unlocked iPhone, you need ultrasn0w so that you can continue using the carrier of your choice even after upgrading to iOS 5.

However, to get ultrasn0w 1.2.4 unlock on iOS 5 your iPhone 4 or iPhone 3GS must have the above mentioned basebands, because ultrasn0w is not compatible with higher basebands such as 3.10.01 and the newer basebands in iOS 5. Before you can proceed to unlock iOS 5 on your iPhone, you must first preserve its baseband before you update it to iOS 5. Follow our guide on how to preserve baseband for iOS 5 unlock and upgrade to iOS 5 by following the steps mentioned in that guide very closely. Once you've done that, return to this guide in order to learn how to unlock iPhone 4, iPhone 3GS on iOS 5 using ultrasn0w 1.2.4.

Attention iPhone 3GS owners: 

there’s a special “trick” that iPhone3GS owners with baseband 06.15 need for iOS5. During the new setup screens you see when you start iOS5 for the first time, you’ll be asked about Location Services. Be sure to select “Disable Location Services” when asked! Later on in the setup, you’ll have the chance to turn on Location Services again when asked if you want to use “Find my iPhone”. It’s fine to turn it back on at that point, if that’s your desire (or you can always go in and enable it in Settings.app)

Update 18/10/2011: After today's redsn0w 0.9.9b6 release, there's no need to do the above mentioned trick. Read more about the new redsn0w release which fixes location services issue on 06.15.00 baseband iPhone 3GS, here.

After preserving unlockable baseband, you need to jailbreak your device. Keep in mind that iOS 5 jailbreak is tethered at the moment and will require you to connect your iPhone 4 or iPhone 3GS to the computer each time the need arises to reboot it. Follow our guide on how to jailbreak iOS 5 firmware using redsn0w on both Windows and Mac. You need the jailbreak because ultrasn0w 1.2.4 can only be installed if your iPhone is jailbroken.

After jailbreaking your device on iOS 5 firmware, follow the steps documented below to unlock iOS 5 firmware using ultrasn0w 1.2.4:

Step 1: Launch Cydia from the Home screen

Step 2: Add the repo666.ultrasn0w.com repository in Cydia. If you don't know how to add a repository, follow this guide. Be sure to enter the URL given in this step.

Step 3: Once you have installed the ultrasn0w repository, simply install ultrasn0w 1.2.4 by going in this repository.

After installation finishes, simply restart your iPhone 4 or iPhone 3GS and it will now work on any carrier of your choice. If you face any problems while trying to unlock iOS 5 firmware using ultrasn0w, don't hesitate to leave a comment down below to ask for help.

  • Midrich

    Hello,
    i have an iphone 3gs with a 06.15.00 ipad baseband. I followed the unlock process as mentioned at your post but still no carrier found when i inserted a sim card.

    • Midrich

      Hello,
      i have an iphone 3gs with a 06.15.00 ipad baseband. I followed the unlock process as mentioned at your post but still no carrier found when i inserted a sim card evn after reflashing the baseband.

      • http://www.iphoneism.com Lota Man

        What is baseband of your iPhone?
        Sent from my BlackBerry® Smartphone provided by Ufone