I would like to upgrade to iOS 4 when it is released. Since I have a jailbroken device, I'll need to restore the firmware. However, I would really like to not lose all my application data, contacts, etc. Is it possible to restore my device from a backup that was created while my device was jailbroken? Is there any jailbroken data in the backup, and would it affect my device if I were to restore from it?