Just a few minutes ago iPhone developer iH8sn0w has pushed out an updated version of Sn0wbreeze 2.2.1 which now supports, Verizon iPhone running iOS 4.2.6, iBooks fix works 100 % and he has also implemented drag & drop IPSW file. The previous version was Sn0wbreeze 2.2R3. The tool comes with minor issues faced in the previous version.
For those who are unaware of Sn0wbreeze jailbreak tool, it helps you build a custom .IPSW file on Windows operating system very similar to the process of creating .IPSW using PwnageTool for Mac.
For those who are unaware of the iBooks restriction, the version 1.2.1 of the iBooks denies to open books on the phones that are jailbroken. It is because Apple has implemented some anti jailbreaking tricks in it. iBooks is implemented with a process which involves the running of unsigned code attempts. These type of attempts are only executed by the jailbroken phones. So it will detect that you are using a jailbroken iPhone and will prompt you a message to restore your iPhone device.
Download Sn0wbreeze 2.2.1 iOS 4.2.1 Jailbreak Tool For Windows OS.