How to unlock Ultrasnow 1.2 Unlocks iPhone 3GS, 3G on iOS 4.2.1

So the iPhone dev team finally released the update version for Ultrasnow. For those of you who don’t know, ultrasnow 1.2 is a free carrier unlock for iPhone3G/3GS with a baseband later than 05.13.04. The unlock for the baseband prior to 05.14 was exploited the AT+XAPP command, thanks to a crash initially discovered by @sherif_hashim (@Oranav also found this crash).

The thing here is that the unlocking process is a bit tricky so read carefully the following instructions on how to unlock iOS 4.2.1 or 4.1 using ultrasnow 1.2.

  1. Unlock requires that your iPhone is jailbroken and you have to update your device’s baseband to 06.15.00 to be able to unlock it. For that you can use PwnageTool 4.1.3.
  2. Once you are done with the jailbreak you can now unlock your iPhone on baseband 06.15.00 using Ultrasn0w 1.2 from Cydia. Here is how you do it.
  • Press to launch Cydia Installer from your SpringBoard.
  • Select the Manage tab at the bottom of the screen.
  • Select the Sources button.
  • Now touch on Edit and then on Add. You will be prompted to enter the URL of the source. Type

    strong> and touch on Add Source to add this repository.

  • Once the source has been added press the large Return to Cydia button then select the Done button at the top right of the screen.
  • Now select from the sources list and at last selectultrasn0w from the list of packages as shown below then install this application.
  1. Almost there, you will need to reboot your iPhone and there you go, you will have a fully unlocked iPhone 3G/3GS on iOS 4.2.1 or 4.1.

Sadly enough iPhone 4 unlockers will have to wait for an unlock that can be used on their device but guess it’s worth it.

And last but not the least this unlock has its own consequences.

1. There is no way to come back down from 06.15, and there’s no hiding the baseband version from Apple.  You’ll be voiding your warranty in a very obvious way.

2. If some future baseband comes out with a critical fix, you won’t be able to update to it if it remains down in the 05.xx sequence (then again, you wouldn’t update to it if you wanted to keep your unlock anyway).

3. Starting with FW 4.2.1 if you have 06.15 on your iPhone you won’t ever be able to restore to stock firmware (it will fail).  You’ll need to only restore to custom IPSWs (then again, if you’re unlocker you should already be doing that).


10 Replies to “How to unlock Ultrasnow 1.2 Unlocks iPhone 3GS, 3G on iOS 4.2.1”

  1. WooHooo!!!! Just unlocked my iPhone 3Gs on 4.2.1 using redsnow 0.9.6b5 and Ultrasnow 1.2.. Awesome anyone needs help please do consult me… Make sure you run redsn0w with Win XP SP3 compatibility.. and your modem baseband is updated to 06.15.00…

  2. Hi, I’ve upgraded my baseband to 06.15.00 with RedSn0w 9.6b5 and running IOS 4.2.1 – I cannot open the UltraSn0w source in cydia whatsoever. Please help – I am going crazy trying to sort this out. Thanks.

  3. 1- Download iOS 4.2.1 from web. You can find it on my sites. Just do a simple search on Google.

    2- Download Redsn0w 0.9.6b5 from web. Again you can find it against a simple Google search.

    3- Unzip the redsn0w file and right click on the redsn0w.exe take properties and under the Compatibility choose Windows XP SP3 to run the file.

    4- Run redsn0w. Browse and select the iOS 4.2.1 file that you have downloaded.

    5- A pop will appear which will confirm whether you have an old iphone or a new one.

    6- You can confirm this from the serial number. For example serial number beginning with 88926. This means the third digit tells you the year that is 2009 and the last two digits tell you the week number. Usually the iPhones from week 40 onwards are considered as new ones. So if you have an any iPhone before week 40 you can click on the “No” button on the pop up.

    7- Press next and let the software create the jailbreak data.

    8- After having Jailbreak data ready you will have multiple options available. Select “Install Cydia” and “Install iPad baseband” and click next.

    9- Now connect your iPhone with the computer and turn it off afterwards.

    10- Follow the steps to get the phone in DFU mode.

    11- First hold the Power button for 3 seconds. Then without releasing the power button press the Home button simultaneously for like 10 seconds. Then without releasing the Home button, release the power button only and keep the Home button pressed for 15 more seconds. Your phone will reboot and redsn0w with load the Jailbreak data.

    12- When phone completely boots up again. You will see Cydia installed which will confirm that that your phone has been Jailbroken.

    13- Connect the phone to some WiFi connection and run Cydia. In Cydia select the Search tab and search for Ultrasn0w 1.2 and Install it then reboot your phone. It will be Unlocked.

    I hope this helps.

  4. how long did your iPhone 3GS take to reboot after installing ultrasn0w 1.2 in Cydia?
    My iPhone 3GS rebooted after installing ultrasn0w but it hasn’t come back to the normal screen for a long time now (5 min). Is it suppose to be this long?
    Please help

  5. My boot screen is stuck at the Apple system icon stage, and it is moving. This doesn’t look right…

  6. Hi,

    I am stuck at iphone 4 baseband 02.10.04 and version 4.1 ,
    my cydia is at 1.2 version.
    i have jailbroken it in canada but couldnt unlock it on my sim in India. i am stuck at carrier unlock.
    pls help as how can i unlock it???

  7. Thank you! I have a 3g now, working on 06.15.00 baseband and 3.1.2 firmware.It worked perfectly, i accidentally upgraded to 06.15.00 baseband and these instructions came in a moment that i thought that i have to use pwangetool again and again…

    Thank you!

  8. i use redsnow for jailbreaking iphone 3gs 4.2.1,but it stop in itunes logo(in recovery mode) then what can i do?
    please help me i am sucked..

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