As we informed yesterday, iOS 4.0 Gold Master candidate is out in the wild and no wonder we are seeing lots of developers trying their best to jailbreak iOS 4.0 GM build. As we reported yesterday, RedSn0w 0.9.5 beta can jailbreak iOS4.0 on iPhone 3G, however you need to be on official carrier since on updating to iOS 4.0, your baseband will also be updated to 05.13.04 for which no official unlock tool is available yet.
The only way to unlock iOS 4.0 on iPhone 3G/3GS is to preserve the baseband with the help of unofficial PwnageTool v4.0 or by using the updated PwnageTool bundles released by msft.guy specially for iOS 4.0 GM build.
Important Note: This is an unofficial build of PwnageTools and hence not fool-proof way of unlocking iOS 4.0. In case you are not an advanced user who knows the iPhone inside out, it is better to stay out of using these unofficial bundles and wait for the iPhone dev team’s release which is expected anytime soon.
Others who understand the risks can use the guide below to Jailbreak iOS 4.0 on iPhone using Pwnagetool bundles. Before proceeding, you would need to download these files
Guide to Jailbreak iOS 4.0 on iPhone 3GS
1. Download iPhone 3GS 4.0 Bundle and all the tools and place it on Desktop.
2. Right click Pwnagetool.app (Pwnagetool 3.1.5 for Mac OS X) and click on ‘Show Package Contents’.
3. Browse to Contents > Resources > Firmware Bundles
4. Now copy the custom bundle iPhone2,1_4.0_8A293_bundle.bundle from iPhone2,1_4.0_8A2943_bundle.zip to FirmwareBundles of Pwnagetool.app
5. Right click on redsn0w.app and ‘Show Package Contents’ and browse to Contents > MacOS. Copy Cydia.tar.gz on your desktop and extract its content.
6. Copy Cydia into PwnageTool.app. For this, you need to right click on Pwnagetool.app and ‘Show Package Contents’. Browse to : Contents > Resources > CustomPackages, right click on ‘CydiaInstaller.bundle’ and ‘Show Package Contents’ > Files, and overwrite all the files with the ones you just extracted from redsn0w.
7. Now load PwnageTool.app and create iOS 4.0 custom firmware for iPhone 3GS
8. Once you got the custom .ipsw, you need to restore iOS 4.0 via iTunes. Your iPhone device must be jailbroken. Put the device in recovery mode and restore.
That is it! You must have now jailbroken your iOS 4.0 on iPhone 3GS. You can use UltraSn0w or BlackSn0w to unlock your jailbroken iPhone.