The Chronic Dev Team has finally released the greenpois0n jailbreak tool for Windows, with Mac and Linux versions expected to be following soon.
The greenpois0n jailbreak tool was supposed to launch earlier, but was delayed when iOS hacker geohot released his own limera1n, which was developed with comex.
The jailbreak tool was based on a boot ROM exploit called SHAtter, developed by Chronic Dev Team member ipod2g, and can be used to jailbreak Apple devices running on iOS 4.1.
As the boot ROM is set when the device is at the factory, it will hard for Apple to patch any boot ROM exploits and virtually impossible to do so on iOS devices in the wild.
However, when geohot released the limera1n jailbreak tool, the Chronic Dev Team decided to modify greenpois0n to use exploit used in limera1n and preserve the boot ROM exploit for later, when Apple patches geohot's exploit.
According to the Chronic Dev Team, greenpois0n can be used to jailbreak almost all Apple devices, iPhone 4, iPhone 3GS, third-gen and fourth-gen iPod touches, and iPads.