Ultrasn0w 1.2 Unlocks iPhone 3GS, 3G on iOS 4.2.1 [How to Guide]

The iPhone Dev Team has just released ultrasn0w 1.2 which brings carrier unlock for iPhone 3GS and iPhone 3G on iOS 4.2.1 or iOS 4.1.

From the iPhone Dev Team Blog:

Today we’re pleased to announce our free carrier unlock for iPhone3G/3GS owners with a baseband later than 05.13.04.  The unlock for that baseband exploited the AT+XAPP command, thanks to a crash initially discovered by @sherif_hashim (@Oranav also found this crash).  So what hole are we exploiting today, since Apple closed that AT+XAPP hole?  Well, we’re exploiting the exact same hole!

It turns out that the very first iPad firmware 3.2.2 has baseband version 06.15.00 still vulnerable to AT+XAPP.  The iPad baseband is built for the exact same baseband chip as the iPhone3G/3GS — they’re fully compatible!  Some of us have been running 06.15 for weeks now on our iPhones in preparation for this release.

Since 06.15 is a higher version than 05.14 or 05.15 (where AT+XAPP is gone), anyone stuck at those versions can simply upgrade to 06.15 to unlock again!  Luckily for us, Apple *still* provides the iPad FW 3.2.2 with this vulnerable baseband right from their own servers. (Grab it now, before they take it down!)
We’ve been busy updating both PwnageTool and redsn0w to make the baseband update as seamless as possible.

1. First up is “PwnageTool 4.1.3 Unlock Edition”.  It has a special dialog box which will ask you if you want to update to the iPad baseband.  You must already have the iPad 3.2.2 IPSW on your computer….so just point PwnageTool at it (or let it find it on its own if you’re in “simple” mode).
2. Directly after PwnageTool 4.1.3 is available, the official ultrasn0w repo http://repo666.ultrasn0w.com will be updated with ultrasn0w 1.2, which covers iPhone 4 baseband 01.59.00 and iPhone 3G/3GS basebands 04.26.08, 05.11.07, 05.12.01, 05.13.04 and now 06.15.00.
3. Finally, we’ll release an update to redsn0w today for those without Macs and can’t run PwnageTool.  The new redsn0w will give you the option to update your baseband to 06.15 too.

WARNING — YOU DO THIS AT YOUR OWN RISK!  PLEASE UNDERSTAND THE CONSEQUENCES OF UPDATING TO 06.15.

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).

Certainly don’t update to 06.15 if you don’t need to!  Only do this if you need the unlock and you’re stuck on 05.14 or 05.15, and you’re willing to assume the above risks.

This PwnageTool also contains a 4.2.1 bundle for iPhone3G owners…for all else, it’s still only 4.1.  If you have an iPhone3GS with an old bootrom, the new redsn0w will handle 4.2.1 for you (in fact it covers 4.2.1 for all devices, even though some of them are still tethered at 4.2.1 until @comex can work some untethering magic).  iPhone3GS users with old bootroms who want to go to 4.2.1 should not use this PwnageTool!  Update to stock 4.2.1 first, then use the upcoming redsn0w to update your baseband.

Please feel free to use our comments section for questions.  We have some very knowledgeable and helpful moderators:  angiepangie, Confucious, dhlizard, and Frank55!

Official Bittorrent Releases

PwnageTool 4.1.3  – PwnageTool_4.1.3_Unlock_Edition.dmg.5994102.TPB.torrent
SHA1 Sum = adda6d882dce1b5117d01586037de289407e038a

Simply follow the instructions posted below to unlock your iPhone 3GS / 3G on iOS 4.2.1. / 4.1 on 05.15.04 and 05.14.02 basebands.

How to: Jailbreak iPhone 3GS / 3G on iOS 4.2.1:
STEP 1: Unlocking requires that your iPhone is jailbroken. Follow our updated guide posted here to use PwnageTool to update your baseband so you can unlock.

How to: Unlock iPhone 3GS / 3G on iOS 4.2.1:
STEP 2: Once you jailbreak yoour device, you can now unlock your iPhone on baseband 06.15.00 using Ultrasn0w 1.2 from Cydia. To do so, follow the steps below:

• Press to launch Cydia Installer from your SpringBoard.
• Press to select the Manage tab at the bottom of the screen.
• Press to select the Sources button

• Now touch on Edit and then on Add. You will be prompted to enter the URL of the source. Type http://repo666.ultrasn0w.com 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 repo666.ultrasn0w.com from the sources list and at last select ultrasn0w from the list of packages as shown below then install this application.

STEP 3: Almost done, now simply reboot your iPhone and you should have a fully unlocked iPhone 3GS on iOS 4.1 or iOS 4.2.1.