Last week, the PwnageTool bundles for the iPhone 4 and iPod Touch 4G was released to jailbreak iOS 4.3 GM on the respective devices. Now the bundles to jailbreak iPhone 3GS iOS 4.3 GM has been released by iH8sn0w. But this is also a tethered jailbreak, so you’ll have to get your device into a jailbroken state after every reboot (Instructions are given below).

Jailbreak iPhone 3GS 4.3 iOS GM Old / New Bootrom

1. Download PwnageTool 4.2.

2. Download the PwnageTool bundle for iPhone 3GS iOS 4.3 GM from here

3. Download iOS 4.3 GM firmware for iPhone 3GS from here

4. Move all the files to the desktop.

5. Right click the PwnageTool 4.2 icon and choose ” Show Package Contents “.

6. Browse to Contents/Resources/FirmwareBundles/ and paste the Old / New Bootrom bundle file here.

7. Download Ramdisk Fixer 1.5 from here and install it.

8. Now start PwnageTool and choose the expert mode.

9. Browse to the iOS 4.3 GM firmware IPSW.

10. Click on the build button after you chose the iOS 4.3 IPSW.

11. Launch iTunes and let it detect your iPhone.

12. Now restore your iPhone 3GS to this newly created iOS 4.3 GM firmware. Go to iTunes and hold the alt key and click on ” Restore “. Now browse to the cooked firmware and select it. Wait till the iPhone reboots.

Tetheredboot Instructions

1. Download TetheredBoot from here and extract it.

2. Make a copy of the iPhone 3GS iOS 4.3 custom firmware and change its extension to .zip.

3. Extract the custom iOS 4.3 zip file you just created.

4. Now copy the files under /Firmware/dfu/.

5. Move the kernelcache.release.n90 and iBSS.n90ap.RELEASE.dfu files to the tetheredboot utility folder.

6. Now, switch off your iPhone 3GS and launch Terminal and enter the following commands :

sudo -s

cd /User/Desktop/Tetherboot/

./tetheredboot iBSS.n90ap.RELEASE.dfu kernelcache.release.n90

7. You will be asked to enter DFU mode. For that, hold the power and home button together for 10 seconds and then release the power button but keep holding the home button for another 10 seconds. Then release it.

That’s it! You have done it! After the reboot, you’ll find your iPhone 3GS jailbroken on iOS 4.3 GM.