I hate the moment when I have to reinstall packages after updating or restoring the firmware. There are a few applications making jailbreak and activation easy. Sync movies, music, contacts, bookmarks are relatively easy using properly configured iTunes. Well it takes a while but at least the phone doesn’t need babysitting during synchronization. However installing desired applications I had before is a different story. I have to install them one by one.

Let’s use the power of Debian to perform the task.

The following instructions will work only with packages installed using Cydia.

1. First we need a backup of our list of installed packages before update/restore the firmware.
2. Use terminal or PuTTY. You have to be a root. Here is the magic command creating you backup list: “dpkg --get-selections > /private/var/MyPackages.list”
3. Transfer /private/var/MyPackages.list to your PC or MAC using your favorite application. WinSCP works fine for me.
4. Now you can restore/update the firmware. Jailbreak, activate and unlock. You will need Cydia installed for the next step.
5. Transfer MyPackages.list from your computer to the iPhone. Remember the directory you placed it. I’ll use /private/var.
6. SSH to your phone or use terminal. Make sure you are root.
7. Restore your packages selection using the following command “dpkg --set-selections < /private/var/MyPackages.list”
8. Make sure the APT is up to date. “apt-get update”
9. Install selected packages /from your backup list/. “apt-get dselect-upgrade” will make it happen.
10. Restart the springboard and you are all set.

that's awesome. Very nice tutorial

Apt Power !!!!

Best post I've found for the jailbreak community. What a time saver!!! Good work on this. And so easy, too. My phone keeps on getting hung up on boot because I'm loading it up with too many apps and music. I think I need to leave more empty space on the drive which is lame, but it's better than crashing and restoring every other day.

This one does the same function as AptBackup in Cydia?

doesnt work for me :S

im trying 2 transfer my old 2g apps to my new 3g iphone

any help please?

Here's the link on how to use AptBackup. It must be doing the same type of thing. Restores your apps, but you loose your settings.

how-to-upgrade-in-itunes