The recent tweet from Joshua Hill of the Chronic Dev Team suggests that the Greenpois0n will be updated to support jailbreak for all iDevices running on iOS 4.2.1 after completing new sandbox patches. Greenpois0n uses Geohot’s bootrom USB exploit used in limera1nand not the SHAtter jailbreak exploit which has been leaked.

Updated version of greenpois0n coming whenever I finish adding these new sandbox patches, sorry this has taken so long