Few hours ago Apple rolled out iOS 4.3 GM 8F190 Build to developers. But as usual the jailbreak community has managed to develop a new PwnageTool bundle to support semi-untethered jailbreak on iPhone 4 running on iOS 4.3 GM.
As mentioned above it is a semi-untethered jailbreak, so you have to connect your iPhone 4 with PC for a successful reboot. This jailbreak process is very useful for developers who want to test their apps before the release of iOS 4.3 public version.
Here is the complete step by step guide to jailbreak iOS 4.3 GM Build 8F190 on iPhone 4 using PwnageTool.
Part 1: Download the Required Tools:
Download the following tools before you start the actual jailbreak process:
- Download latest iTunes 10.2 and install it on your Mac machine.
- Download PwnageTool
- Download PwnageTool bundles for iPhone 4 (Bundles for more devices will be added later)
- Download Universal Ramdisk Fixer
- Download iOS 4.3 beta 3 (devs only)
Disclaimer: This guide is for testing and educational purposes only. Please don’t follow the steps mentioned below if you don’t know what you are going to do. We won’t be responsible for any damage to your anything.
Note: Those users who rely on unlock should not try this guide.
Part 2: Patching / Modifying PwnageTool using custom bundles
Since official Pwnagetool doesn’t support iOS 4.3, we have to modify it using the custom PwnageTool bundles.
Step 1: Right click on the PwnageTool which you download in Par-1 and then click on “Show Package Contents”.

Step 2: Navigate to this path /Contents/Resources/FirmwareBundles and put the bundle folder which you downloaded for your device in Part 1 in this location.
Step 3: Close the folder.
Part 3: Patching Ramdisk
Now we have to fix the broken PwnageTool ramdisk process to support iOS 4.3 GM.
Step 1: Launch Universal Ramdisk Fixer.


Part 3: Creating Custom iOS 4.3
Step 1: Launch the updated iTunes.
Step 2: Back up your device.
Step 3: Launch modified PwnageTool.
Step 4: Now select your iPhone and click the blue arrow to continue.

Step 5: Browse for iPSW file (iOS 4.3 GM) which you have already downloaded in Part 1. (Make it sure that iPSW file is placed on desktop)

Step 6. Now hit the Build button to cook the custom firmware and save it on your PC.

Part 5: Restoring iOS 4.3 Custom Firmware
Put your iPhone into DFU mode. PwnageTool will help you in this process. Follow the onscreen instructions for this purpose.
- 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
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.
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.
Part 6: Booting the Device in Tethered Boot
Since iOS 4.3 jailbreak is tethered, we will have to connect the device with PC and use a software “tetheredboot” to boot it into a tethered jailbroken state.
Tetheredboot utility requires two files from iOS 4.3 to do its jobs. The names of those files are
- kernelcache.release.n90,
- and iBSS.n90ap.RELEASE.dfu.
To get these files, change the extension of iOS 4.3 from .ipsw to .zip and extract it. You will find them under /Firmware/dfu/ folder.
Put all these files and tetheredboot utility into a new folder on desktop and name it “tetheredboot”.
Now connect your device with your computer and boot it into Recovery Mode by holding power and home button until “Connect to iTunes” screen appears on iPhone.
Start terminal and run the following commands:
sudo sh
type your admin password and run:
/Users/SarmadKhan/Downloads/tetheredboot/tetheredboot
/Users/SarmadKhan/Downloads/tetheredboot/iBSS.n90ap.RELEASE.dfu
/Users/SarmadKhan/Downloads/tetheredboot/kernelcache.release.n9
Replace “SarmadKhan” with the name of directory on your Mac machine.
When you are asked to put your device into DFU mode, follow the same method you used in Part 5. After a short period of time you will see “Exiting libpois0n” in the terminal windows which indicates your iPhone, iPad, iPod Touch will be booted within few moments.
[Thanks Redmondpie For some of the pics}
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