Corona

Corona is a Cydia package from the Chronic Dev Team on Saurik's repo. It uses pod2g's Racoon String Format Overflow Exploit and an HFS Heap Overflow to untether iOS 5.0.1 on previously-jailbroken devices. Alternatively, users can also re-run the iPhone Dev Team's redsn0w 0.9.10 to untether their jailbreak with the same exploit. The name is an anagram of the aforementioned racoon software.

A5 Jailbreak
According to pod2g's blog, he was having problems with the app sandboxing system used on the A5 processor in the iPad 2 and iPhone 4S, so he got planetbeing, MuscleNerd, Joshua Hill and saurik, dubbed the "dream team", to help to fix it. Dustin Howett also demoed the A5 jailbreak on YouTube. It was released on 20 January 2012 as Absinthe.

Details
All this package essentially does is disable ASLR to enable the untether portion of absinthe. It does this by just changing the launchd's config file1-31 from DisableAslr to DisableAslr

Changelog

 * 1.0-8 Fixed an issue were corona failed on iPhone 4S on iOS 5.0
 * 1.0-7 1.0-6 had a "Depends" that made it refuse to install on an original iPad.
 * 1.0-6 fixed iBooks issues (books having DRM may show half pictures and/or grey rectangles).
 * 1.0-5 was updated by Saurik again to require a reboot after installing.
 * 1.0-4 includes sandbox patches by comex that fixes iBooks problems, as well as another fix for launchctl.
 * 1.0-3 was updated by Saurik to enable redsn0w 0.9.10 users to update the jailbreak through Cydia.
 * 1.0-2 attempted to fix a bug that caused launchctl to not start daemons on-demand.
 * 1.0-1 is the initial release of the jailbreak.