The fix for iBooks was earlier available only in PwnageTool 4.2 for Mac and Sn0wbreeze 2.2 for Windows that were released earlier in the week. Chronic Dev Team has incorporated the same fix in the latest version of greenpois0n.
iPhone users who want to preserve the baseband from getting upgraded so that it can be unlocked should use PwnageTool or Sn0wbreeze. iPad, iPod Touch and iPhone users (who don’t care about unlocking) should use greenpois0n as it is faster and a lot easier to use.
Mac users can follow our step-by-step guide to jailbreak their iOS devices on iOS 4.2.1 using greenpois0n below:
Windows users can follow the appropriate step-by-step guide:
If you’ve used greenpois0n RC5 or RC6 to jailbreak your iOS device then you can just run greenpois0n RC6.1 on top of it without restoring.
Please note that jailbreaking your iDevice may void its warranty so proceed with caution and at your own risk. Please don’t forget to backup your iPhone before you proceed. You can refer to this postfor instructions on how to backup your iPhone.
As always, let us know how it goes.