How to Untethered Jailbreak iOS 4.2.1 Using PwnageTool [Mac]

We told you about Dev-Team’s release of PwnageTool 4.2 yesterday. Here’s the full tutorial to Untethered Jailbreak iOS 4.2.1 using a Mac computer. If you have already jailbroken your iPhone 4 using Greenpois0n then you don’t need to jailbreak again. The advantage of PwnageTool over Greenpois0n is that it preserves your baseband and Ultrasn0w unlock.

This tutorial will only help you jailbreak your iPhone 4. Small note for those interested in unlocking iPhone. At present only iPhone 4 with baseband 1.59.00 can be unlocked. If unsure, read How to Find iPhone Baseband Version. So if you are on that baseband you can follow Ultrasn0w unlock guide after jailbreaking your iPhone using these instructions. If on a newer baseband, you will have to wait till an unlock is released.

Tools Required to Untethered Jailbreak iOS 4.2.1

Download these:

Steps to Untethered Jailbreak iOS 4.2.1

Launch PwnageTool after mounting it on your Mac(double click downloaded file) and click on OK when you see the following warning.

Jailbreak iphone 4 ios 421 pwnagetool mac 1

Click on Expert Mode at the top.

Click on the iPhone’s icon and then on the blue arrow to proceed.

Now tap on browse for IPSW and point it to the firmware file you downloaded above and click on open.

Click on General and then on Next arrow. Select Activate the iPhone if you are not using a SIM from official carrier. If on official carrier make sure you deselect the option.

Now click on Back and then on Build. When you press the next button you will be asked where to save the custom firmware file. Your IPSW is now being saved.

A minute or two later you will be asked to enter your computer’s password to proceed. After that allow ten minutes to finish building the IPSW file.

Once complete you will be asked to connect iPhone to your Mac. You will now be guided to put iPhone into DFU mode in order to proceed.

Once in DFU mode, close PwnageTool and launch iTunes.

Untethered Jailbreak iOS 4.2.1

In iTunes press Alt button on your Mac and then click on Restore. Point iTunes to the custom IPSW made using PwnageTool.

iTunes will now restore your iPhone and in ten minutes your iPhone will restart jailbroken with Cydia installed.

If on baseband 1.59.00 you can now follow Ultrasn0w unlock guide to unlock your iPhone 4.

Leave a comment about how the tutorial worked for you.