iOS hacker iH8sn0w has released Sn0wbreeze 2.2 for windows with the fix of iBook issue.Like in Greenposi0n, To achieve untethered iOS 4.2.1 jailbreak, Sn0wbreeze 2.2 uses kernel vulnerability feedface in combination with limera1ns bootrom exploit.
Snowbreeze 2.2 New Features
Baseband Preservation Mode: The advantage over the Greenposi0nis that PwnageTool allows you to retain current baseband and unlock of the iOS devices and you can safely restore to a custom 4.2.1 pre-jailbroken IPSW, Like in PwnageTool.
Custom Boot Logo: By definition Custom Boot Logo means that it will replace the default white Apple logo at the boot time with the Custom logo, like in Greenposi0n.Sn0wbreeze 2.2 have custom boot logos to install.
Pacman Game:Custom IPSW firmware build process takes time so to make the jailbreak more enjoyable, hacker has added an interesting option to play Pacman game while the IPSW is being build in sn0wbreeze 2.2.You can easily switch from IPSW building screen and Pacman and vice a verse anytime.
Download Link for sn0wbreeze 2.2
http://hotfile.com/dl/105112824/734b0c0/sn0wbreeze-2.2-final.zip.html
http://www.unigizmo.com/1599/sn0wbreeze-2-2-released-to-jailbreak-ios-4-2-1-custom-firmware-download#more-1599

Snowbreeze 2.2 New Features
Baseband Preservation Mode: The advantage over the Greenposi0nis that PwnageTool allows you to retain current baseband and unlock of the iOS devices and you can safely restore to a custom 4.2.1 pre-jailbroken IPSW, Like in PwnageTool.
Custom Boot Logo: By definition Custom Boot Logo means that it will replace the default white Apple logo at the boot time with the Custom logo, like in Greenposi0n.Sn0wbreeze 2.2 have custom boot logos to install.
Pacman Game:Custom IPSW firmware build process takes time so to make the jailbreak more enjoyable, hacker has added an interesting option to play Pacman game while the IPSW is being build in sn0wbreeze 2.2.You can easily switch from IPSW building screen and Pacman and vice a verse anytime.
Download Link for sn0wbreeze 2.2
http://hotfile.com/dl/105112824/734b0c0/sn0wbreeze-2.2-final.zip.html
http://www.unigizmo.com/1599/sn0wbreeze-2-2-released-to-jailbreak-ios-4-2-1-custom-firmware-download#more-1599