Jailbreak iPhone 3GS on iOS 4.2 with PwnageTool

Possibly the easiest way to jailbreak your iPhone 3GS with the new iOS 4.2 software is to use the PwnageTool. Here is a step by step guide on how to use the PwnageTool to jailbreak your iOS 4.2 iPhone 3GS.

Note: Only iPhone 3GS with old bootrom is supported. Also there are too many jailbroken apps that are currently broken on iOS 4.2. Therefore proceed at your own risk only. I am not responsible if you end up bricking or locking your phone. Proceed if you are an advanced user only, and know what you are doing. Otherwise, wait for the official tools.

Step 1: Download PwnageTool 4.1.2 from the download link given below.

Step 2: Download the latest version of PwnageTool Bundle for iPhone 3GS on iOS 4.2 from here, and then extract it to your desktop.

Step 3: Now download iOS 4.2 GM for iPhone 3GS. You can get the official bits if you are a registered developer, or from different content sharing sites around the web. Please do not ask for the download links, a simple Google will do it all !

Step 4: Copy PwnageTool that you downloaded in Step 1 to a folder on your desktop. Right click, and then click on “Show Package Contents” as shown in the screenshot below.

Step 5: Navigate to Contents/Resources/FirmwareBundles/ and paste iPhone2,1_4.2_8C134.bundle file in this location and then simply close this folder.

Step 6: Now move atvBundlePatcher.sh and Info.plist.patch files to the same directory (on desktop) as the PwnageTool.

Step 7: Now rename atvBundlePatcher.sh to atvBundlePatcher.command and double click this file so that Terminal can execute the script as shown in the screenshot below.

Step 8: Once you are done, close all the open windows and start this patched version of PwnageTool, Select “Expert Mode” and browse for the original iOS 4.2 for iPhone 3GS firmware as shown in the screenshot below.

Step 9: Select “Build” and click next. PwnageTool will now create the custom .ipsw file for your iPhone which will be jailbroken.

Step 10: Now follow the following steps to enter DFU mode:

• Hold Power and Home buttons for 10 seconds
• Now release the Power button but continue holding the Home button for 10 more seconds
• You device should now be in DFU mode

Step 11: You will now have to restore your iPhone 3GS to this custom firmware 4.2 file. Start iTunes, click on your device icon from the sidebar in iTunes. Now press and hold left “alt” button (“Shift” button on Windows) on the keyboard and then click on “Restore” (Not “Update” or “Check for Update”) button in the iTunes and then release the “Shift” button.

This will make iTunes prompt you to select the location for your custom firmware 4.2 file. Select the required custom .ipsw file and click on “Open”.

Step 12: Now sit back and enjoy as iTunes does the rest for you. This will involve a series of automated steps. Be patient at this stage and don’t do anything silly. Just wait while iTunes installs the new firmware 4.2 on your iPhone 3GS. Your iPhone 3GS’ screen at this point will be showing a progress bar indicating installation progress. After the installation is done, your iPhone will restart automatically and you should now have a fully jailbroken iPhone 3GS on iOS 4.2.