Chronic dev finally released the much awaited Greenpois0n tool that can jailbreak all iOS devices untethered on 4.2.1. It works on iPhone 4, 3GS, iPod Touch 2G, 3G, 4G, iPad and Apple TV. It does not require any shsh blobs to be saved.
It is recommended to restore your iDevice to stock 4.2.1 first. However, this will update the baseband. If you have iPhone 4 and need unlock, stay away from this.
- Download Greenpois0n: Download for Mac and Windows
- Open GreenPois0n and click on jailbreak button
- Follow the onscreen instructions to put your iDevice in DFU mode. Once it is complete, Greenpois0n will start jailbreaking your device.
Note: You’ll get some errors initially but it should continue in a few seconds. If not, then start the whole process again.
- Your iDevice should be jailbroken. There should be a “loader” icon on your homescreen. Open it and install cydia.
Thats it. Enjoy the untethered jailbroken iPhone running iOS 4.2.1.
Update: Greenpois0n RC5 for windows released: Download Greepois0n for windows