Saurik is a well known legendary person who joined the pod2g’s A5 untethered jailbreak and makes a major contribution. Corona jailbreak has updated recently with the version of 1.0-5 to fix the iBooks along with the launched framework.
The Corona 1.0-5 update still only supports the iPhone 4, iPhone 3GS, iPad 1 and the 3rd gen iPod Touch and iTouch 4G.
A new blog post from French developer Pod2g, and a tweet from Cydia founder, Jay Freeman, have confirmed that the 1.0.5 Corona update is now live in Cydia which resolves the iBooks issue, along with the launchd socket issue. An initial update to version 1.0.4 briefly went live in Cydia, before Saurik added a force reboot on upgrade and pushed a new version taking Corona to the current 1.0.5 release.
If you already installed Corona as a part of your untethered iOS 5.0.1 jailbreak, then plesae go back to Cydia and simply upgrade it now to the latest version to fix iBooks and other bugs.
For those who are already running iOS 5.0.1 on their A4 chip devices, can follow the full guide posted here to jailbreak 5.0.1 untethered on iPhone 4, iPad 1, iPod Touch 3G/4G using Redsn0w.