Now you can use iBooks on your untethered jailbreak by installing Corona.
If you are addicted to iBooks, then you should download the newest Corona update. It has been updated to patch iBooks from a kernel level so that you can read your iBooks purchases on your iOS 5.0.1 untethered jailbroken iDevice. Before this update, there were sandbox problems that would have prevented you from doing so.
If you are jailbroken from the original Corona untether, then all you need to do is just update the package to get your iBooks patch. It will require a reboot after installing. If you are jailbroken untethered already using the latest redsn0w, then in that case, you can just install Corona over the untethered redsn0w jailbreak for iOS 5.0.1 and the iBooks patch will take affect immediately. The sandbox fix for iBooks has come from a patch made by comex. However, the latest Corona update has not been developed by comex.
Corona was updated to version 1.0-4 fixed iBooks. However, there was another launched problem that was fixed in it and additionally users were not restarting their iDevice after installing it. That is why, they were complaining that the patch did not work. Because of this, Corona 1.0-5 (current version) was released. This update not only fixes iBooks, but also fixes the launched problem again (as cited by a hacker called saurik). However, this update will it will also force you to reboot your iDevice to ensure that the patch will certainly work effectively.
This update is a must download for those of you who have been waiting for an iBooks fix in order to update.