The Dev Team has just released PwnageTool 4.2, a untether jailbreak tool for iOS 4.2.1 for iPhone 3G, iPhone 3GS, and iPhone 4 (AT&T and Verizon), as well as the iPad, Apple TV 2G, and iPod Touch 3G and 4G. PwnageTool 4.2 will allow you to untether jailbreak your iPhone on the latest iOS 4.2.1 while preserving its baseband, thus allowing you to unlock with ultrasn0w, assuming you are still on baseband 01.59.00. This step by step guide will show you how to jailbreak your iPhone iOS 4.2.1 using PwnageTool 4.2, a Mac-only jailbreak tool.






PwnageTool 4.2 supports the following iDevices on iOS 4.2.1 :

* iPhone 3G
* iPhone 3GS
* iPhone 4 AT&T
* iPhone 4 Verizon
* iPod Touch 3G
* iPod Touch 4G
* iPad
* AppleTV 2G


Jailbreak iOS 4.2.1 Using PwnageTool 4.2 [How To] :  


Part 1 : Download the Required Tools

Download the following tools before you start the actual iOS 4.2.1 jailbreak process :

Download iTunes 10.1.2 and install it on your Mac machine
Download PwnageTool for iOS 4.2.1 jailbreak

Part 2 : Creating Custom iOS 4.2.1 Firmware

1) Make sure you are running the latest version of iTunes. If not, download iTunes from above then sync your iPhone. Close iTunes when done.

2) Download the correct firmware iOS 4.2.1 for your iPhone model.

3) Launch PwnageTool, select Expert Mode, then select your iDevice. Click the blue arrow to continue.



4) Now browse for the iOS 4.2.1 firmware you downloaded in  2.


5) Select “General” and click on the blue arrow to continue. If your iPhone is NOT on an official carrier, select “Activate the phone”. If you are on an official carrier (ie. AT&T in the US), make sure this option is deselected. You can also increase the root partition at about 1,000 MB. Click the blue arrow to continue.






6) You are now in Cydia settings. From there, you can choose to pre-install jailbreak apps so that you don’t have to do it later. Select this option if you want to pre-install apps now. When done, click the blue arrow to continue.

7) You are in “Custom packages settings”. By default, “Cydia Installer” should be selected. Make sure it is selected and click next.

8) Click “Build”, then click the blue arrow.


9) Select where to save your custom firmware. If prompted, enter your password.



10) PwnageTool will now build your custom IPSW, which should take a few minutes.




Part 3 : Restoring iOS 4.2.1 Custom Firmware

Put your iPhone in DFU mode. PwnageTool 4.2 will help you in this process. Follow the onscreen instructions for this purpose.


1) Hold Power and Home buttons for 10 seconds
2) Now release the Power button but continue holding the Home button for 10 more seconds
3) You device should now be in DFU mode
4) After the iPhone is in DFU mode, launch iTunes and it will tell you it has found an iPhone in recovery mode. Press OK to continue.
5) To install the custom cooked firmware, press the Alt/Option key and click on “Restore” in iTunes.

Now wait for few minutes until iTunes does its job. The iPhone will reboot after it has been restored successfully.

Now you have successfully untethered jailbroken your iPhone using PwnageTool 4.2, you should have the Cydia icon on your springboard. Depending on your baseband version, you will be able to unlock using Ultrasn0w unlock tool using the tutorial here. Let us know how it worked out for you by leaving a comment below.