Have you encountered that message above?
There is a problem with the configuration of your iPhone. Please restore with iTunes and reinstall iBooks.
Are you looking for a fix for iBooks after jailbreak iOS 4.2.1 via Greenpois0n? A solution is now available in Cydia that will solve the problem of iBooks refusing to open content on jailbroken devices.
Here’s How to Fix the iBooks Error via Cydia
1. Launch Cydia –> Manage –> Sources –> Edit –> Add
2. Enter the following repository: http://repo.insanelyi.com , tap Add Source
3. Search for’iBooks Fix’ and install it.
After the install of iBooks Fix, you should be able to read your books on iOS 4.2.1. By installing this tweak via Cydia, you won’t have to re-jailbreak with PwnageTool 4.2/sn0wbreeze 2.2 to fix iBooks. This will save some time and trouble.
Let me know how iBooks Fix works for you. Happy reading. 🙂