Dev Team has just released PwnageTool 4.2 to untethered jailbreak for all devices running iOS 4.2.1 with the help of Greenpois0n exploit....

Dev Team has just released PwnageTool 4.2 to untethered jailbreak for all devices running iOS 4.2.1 with the help of Greenpois0n exploit. As you know PwnageTool is a Mac OS X tool, this version support all iOS devices except iPod touch 2G.

Supported device:

• iPhone3G
• iPhone3GS
• iPhone4
• iPhone4-Verizon
• iPod touch 3G
• iPod touch 4G
• iPad
• AppleTV 2G

Important note: If you rely on ultrasn0w unlock, you MUST use this version of PwnageTool which creates custom 4.2.1 firmware with preserving the unlockable baseband to be able to unlock your iPhone again using ultrasn0w 1.2

You can jailbreak your iOS device running iOS 4.2.1 using PwnageTool 4.2 by following our previous guide posted here.

Note: In the above guide you Must use PwnageTool 4.2 and select iOS 4.2.1 IPSW.

Download PwnageTool 4.2 for Mac
Download iOS 4.2.1 for all iPhone, iPod touch, iPad and Apple TV 2G

 link