Chronic Dev Team’s Joshua Hill, aka p0sixninja, has gone public with his statement that there will soon be an updated version of GreenPois0n that will support iOS 4.2.1 jailbreak. Only a few sandbox patches remain to be put in place.

GreenPois0n uses Geohot’s Limera1n bootrom exploit that pwns all iOS devices permanently. There were rumors that Apple had fixed the exploitable that Limera1n used.

From all indications GreenPois0n will probably be a tethered jailbreak similar to Redsn0w 0.9.6b6. Again this tethered or semi-tethered jailbreak may work only on the new iOS devices like the iPhone 3GS with the new bootrom, iPhone 4, iPad, iPod touch 2G (MC Model), iPod touch 3G and iPod touch 4G.

At present older iPhone 3GS with the old bootrom, iPhone 3G and iPod touch 2G (Non-MC model) can have an untethered jailbreak. This can be done through Redsn0w 0.9.6b6. Untethered jailbreaks require use of Redsnow 0.9.7 where the SHSH blobs of iOS 4.2b3 need to be saved for the jailbreak to be successful. In case the SHSH blobs of iOS 4.2b3 were not saved then Comex untethered jailbreak tool can be used. This jailbreak tool may be released once Apple releases its next iOS firmware.