The Dev-Team has also updated PwnageTool for Mac to jailbreak iOS 4.3.1 but Redsn0w is not only available to both Windows and Mac users but also offers a faster jailbreak process since it does not require any custom IPSW to be created.

Note: Please read through the below notes before taking action to jailbreak your iPhone

The jailbroken only compatible as listed below using this tool.
  • iPhone3GS
  • iPhone4 (GSM)
  • iPod touch 3G
  • iPod touch 4G
  • iPad1
  • AppleTV 2G (PwnageTool only for now)
  • If your iPhone is not factory unlocked and you use Ultrasn0w on your iPhone 4 or iPhone 3GS then please note that Ultrasn0w does not work with iOS 4.3.1 at the moment. The Dev-Team will be releasing an updated Ultrasn0w in Cydia soon.
  • You must not update your iPhone with stock firmware from Apple. In order to preserve the iPhone baseband, upgrade to iOS 4.3.1 using custom IPSW created in PwnageTool or by using TinyUmbrella only.
1. You must first download Redsn0w and the iOS 4.3.1 firmware in order to proceed with the jailbreak. Here are the links:

redsn0w 0.9.6rc9:

iOS 4.3.1 Official Firmware

2. Launch iTunes and connect your iPhone using the dock connector to USB cable. Now press Alt key on your Mac’s keyboard and click on Check for update. Windows users need to press the Shift key and then click on update. Since, RedSn0w does not create any custom IPSW you need to update your iPhone to iOS 4.3.1 before performing the jailbreak.

3. You can now select the IPSW file downloaded in the previous step to update your iPhone. In less than ten minutes, your iPhone will update and reboot.

4. Extract the RedSn0w zip archive we downloaded earlier and launch redsn0w.

5. Now click on Browse and select the IPSW file corresponding to your iPhone or other iOS device that you are jailbreaking.

6. RedSn0w will now try to identify and process the firmware file automatically. Once the firmware file has been identified click on Next. RedSn0w will now start preparing jailbreak data based on the IPSW file.

7. By default the checkbox beside Install Cydia should be selected. You do not need to change any settings here. Click Next to proceed.

8. You need to turn off your iPhone or iPod Touch after connecting it to the computer. Click on Next again. The next screen will show you instructions to put the iOS device into DFU mode.

9. You need to hold and release the iPhone buttons in the said order to place it in DFU mode in order to proceed with the iPhone jailbreak. This is the last step for the user as after this RedSn0w will do everything automatically.

10. The iPhone will be jailbroken and then rebooted.

11. Click on Finish when you see Done! on your screen.

12. Now jailbreaking process has complete with iPhone 4.3.1 iOS. Finally, sync back your iPhone to restore your backups data with iTunes.

13. For beginner user, you might be want to know what to do after Jailbreak. Check out my post here on how to use Cydia. For those who already knew about Cydia you could ignore this step.