How to Jailbreak and Unlock iOS 4.2.1 on iPhone 3G using PwnageTool [Mac]

As you might have already heard the Ultrasn0w iOS 4.2.1 unlock has been released and the iPhone 3G users benefit the most. The Jailbreak + Unlock process may look hectic and confusing at first glance but it actually is very simple and anyone with no jailbreaking experience can do it using this guide.

We are going to jailbreak and unlock iPhone 3G on iOS 4.2.1 firmware using the PwnageTool for Mac.

What Files do you need?

1. iOS 4.2.1 firmware file(.IPSW) for iPhone 3G

Here’s the direct download link. For more firmware links head over to our post – Where to Download iPhone firmware from.

2. If you are on baseband 05.14 or 05.15 you will need an additional iPad 3.2.2 firmware file during unlocking. Download it from here(3.2.2: iPad1,1_3.2.2_7B500_Restore.ipsw)

3. PwnageTool for Mac

Get it from any of the following links:


Now follow these steps carefully to jailbreak your iPhone.

Jailbreak iOS 4.2.1 Procedure:

Launch the PwnageTool and select “Expert Mode” from top menu.

jailbreak iOS 4.2.1

Click on the image of iPhone from the screen presented.


Now select Browse for IPSW and select the firmware file you download in the very first step.


You will then be asked about the baseband upgrade. This is the part which confuses most people. So we have tried to make it much simpler for you by showing a few common scenarios. You’ll most likely fit into one of them.


  • I only want Jailbreak for my iPhone and not the unlock: Select No. You don’t need to upgrade baseband.
  • Ultrasn0w works for me right now. I want to preserve unlock on iOS 4.2.1: Select No. Since it won’t make a difference for you it’s better to not upgrade.
  • My iPhone is on 05.14 or 05.15 baseband: You must select Yes. You don’t have any other option if you need an unlock.

In case you don’t know your iPhone’s firmware version or baseband version take a look at our detailed guide to find out iPhone firmware and baseband version.

If you selected Yes in the Baseband upgrade question, browse for the iPad IPSW. If you selected No, proceed to next step.


Select General Settings and select Activate the Phone if you are not using official carrier to activate. For example, if you are jailbreaking iPhone purchased from Airtel while using an Airtel SIM you should deselect this option.


You don’t need to do anything else here. Proceed to IPSW build by selecting Build and clicking on Next.


Save the custom .IPSW file. Normally takes around five minutes to complete. PwnageTool will ask you to enter your password once before building the custom file.

Now the major work is done. Connect iPhone to your computer. It needs to be put into DFU mode before we restore it in iTunes.

When PwnageTool asks you if your iPhone has been Pwned before, select No.

Press iPhone buttons in the sequence showed on screen. In case you fail in first attempt, don’t worry and patiently try again.


Once iPhone is in DFU Mode open iTunes and press Alt/Option + Restore and point iTunes to custom IPSW file that we just made.

In around ten minutes your iPhone should restart with a jailbroken iOS 4.2.1 firmware.

Those who need an unlock should download Ultrasn0w from Cydia. Here’s the full guide to show you How to Unlock iOS 4.2.1 using Ultrasn0w.

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