Thursday, December 2, 2010

How To Unlock iOS 4.2.1 for iPhone 3G/3GS using Redsn0w and Ultrasn0w

How To Unlock iOS 4.2.1 for iPhone 3G/3GS using Redsn0w and Ultrasn0w
As you know, the iPhone Dev team has released Ultrasn0w 1.2 to unlock iPhone 3G and 3GS with baseband 05.13.04 or up. To use Ultrasn0w, you’ll need to jailbreak your iPhone and upgrade it to the iPad’s baseband. The whole unlock process is more complex compared with all those unlocks you’ve done before. I do [...]

As you know, the iPhone Dev team has released Ultrasn0w 1.2 to unlock iPhone 3G and 3GS with baseband 05.13.04 or up. To use Ultrasn0w, you’ll need to jailbreak your iPhone and upgrade it to the iPad’s baseband. The whole unlock process is more complex compared with all those unlocks you’ve done before.

I do not recommend you to upgrade to iOS 4.2.1 if you’re already using an unlocked iPhone 3G or 3GS running iOS 4.0. That’s good enough and iOS 4.2.1 is not a big update. But in case you’ve accidentally upgraded to iOS 4.2 and are waiting for the unlock solution, you can follow this guide and use Ultrasn0w to unlock your iPhone.

Read It Carefully Before You Take Action

Before you proceed, you must read through the below notes very carefully.

  • This guide is for iPhone 3G and iPhone 3GS ONLY. If you’re using iPhone 4 running iOS 4.1 (or up) and searching for unlock solution, this guide will not work for you. Presently there is no unlock solution for iPhone 4 running iOS 4.1 or up.
  • If you just want to jailbreak your iPhone 3G/3GS on iOS 4.2, this guide is NOT for you. Please check out our Complete Guide about How To Jailbreak iOS 4.2.1 using Redsn0w.
  • To unlock iPhone 3G/3GS on iOS 4.2, you’ll need to tweak the baseband and upgrade it to the one used by the iPad (i.e. 06.15). Once you’ve done so, 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.
  • In future, when baseband update comes out with a critical fix, you won’t be able to update to it if it remains down in the 05.xx sequence.
  • Once you follow this guide to unlock your iPhone, your iPhone you won’t ever be able to restore to stock firmware. The restore will fail as the baseband has been updated to the iPad one. In case you need to restore, you’ll need to only restore to custom IPSWs.
  • Base on the reports from some users, the unlock works. However, some experienced WiFi and GPS problems.
  • If you’re using newer model of iPhone 3GS (i.e. with new bootrom), only tethered jailbreak is supported.
  • Lastly, do it at your own risk and understand you’ll void the warranty of your iPhone.

Okay, enough for the warnings and let’s get started.

Preparation for the Jailbreak and Unlock

1. First, download Redsn0w 0.9.6beta5 from here (Windows / Mac). Unzip the file after download completes.

2. Download the firmware file for iOS 4.2.1. For iPhone 3G, please download iPhone1,2_4.2.1_8C148_Restore.ipsw. For iPhone 3GS, please download iPhone2,1_4.2.1_8C148a_Restore.ipsw.

3. Launch iTunes and connect your iPhone to your computer. Backup your iPhone data by synchronizing it with iTunes.

4. Once you complete the backup, restore your iPhone to iOS 4.2.1 with the firmware file you’ve downloaded. For Windows, you can press SHIFT and click “Restore” button to select the firmware file. For Mac OS, simply press OPTION and click “Restore” button to select the firmware file. It’ll take some time for the restoration process. Just sit back and wait until it completes.

Jailbreaking and Upgrading Baseband with Redsn0w

5. Now your iPhone should be upgraded to iOS 4.2.1. Open “Redsn0w”.

6. Click “Browse” button and select the firmware file (.ipsw) you downloaded in step 2. Make sure you select the correct firmware file. For iPhone 3G, please select iPhone1,2_4.2.1_8C148_Restore.ipsw. If you’re using iPhone 3GS, please select iPhone2,1_4.2.1_8C148a_Restore.ipsw.

7. Redsn0w will then verify the IPSW file. If you’re using iPhone 3GS, at some point of the process, it prompts you a dialog asking whether you’re using a newer model. Just follow the instruction to determine the model of your device. If it’s a newer one, answer “Yes”. Otherwise, just click “No”.

8. Click “Next” once the IPSW is identified.

9. Redsn0w will then prepare the jailbreak data.

10. Select “Install Cydia” and “Install iPad baseband”. When you select “Install iPad base”, Redsn0w will prompt a warning dialog. Just click “Yes” to confirm.

11. Make sure your iPhone is connected to computer and switched OFF. Click “Next” to continue.

12. Follow the on-screen instructions to put your iPhone into DFU mode.

13. If you’ve successfully put your iPhone into DFU mode, redsn0w will then download the iPad baseband and jailbreak your iPhone. Keep your iPhone connected until the whole process completes.

When the jailbreak process finishes successfully, your iPhone will be rebooted and you’ll be able to find Cydia installed on the iPhone.

Unlocking Your iPhone with Ultrasn0w

14. Once jailbroken, you can now launch Cydia on your iPhone.

15. Search for “Ultrasn0w” and install it.

If everything goes fine, your iPhone should be unlocked to allow you to use any SIM card.

For iPhone 3GS (New Bootrom) User

In case you’re owning an iPhone 3GS with new bootrom, the current version of Redsn0w only supports tethered jailbreak. Every time you reboot the iPhone, you’ll need to connect it to computer and use Redsn0w to jailbreak it again. You can simply select the “Just boot tethered right now” option.




Olivia Wilde
Megan Fox

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