Today I upgraded my iPhone to 3.0.1. There isn't an official jailbreak for 3.0.1 yet, but the 3.0 jailbreak works. The problem in general with upgrading a jailbroken phone is that there's no real way to back up all of your unauthorized customizations. You've basically had your way with the underlying Unix OS. Not everything you install from Cydia is a self-contained app. There are system modifications like installing OpenSSH and system utilities. Anyway, what it comes down to is that you need to reinstall all of your Cydia packages after upgrading and re-jailbreaking.
Here's how the process went for me:
-do a backup
-choose to restore, which will also update. Don't choose upgrade.
After this is done, leave itunes, and follow the normal jailbreak process
-Point redsn0w at your 3.0 iPhone OS ipsw file.
Once redsn0w is done, you're jailbroken again and running (mostly) 3.0.1. You still need to reinstall your Cydia packages. I found some of my customizations returned once I had reinstalled the Cydia packages, but not all.
On the topic of Cydia packages, here's a list of packages that I installed and really like:
- BigBoss Recommended; This gets you a bunch of command line utilities that you'd expect to be on most unix systems. It actually is a metapackage that brings a ton of other packages with it.
- MobileTerminal; A terminal application (not an SSH client)
- MusicControls; A paid app that lets you background and control many music applications like Slacker and Pandora
- OpenSSH; client and server. Be sure to reset passwords for root and mobile. Also disable root logins. Disable sshd from running automatically.
- SBSettings; let's you tweak many hidden settings, replacing BossPrefs. Also required for disabling autostarting of the sshd service
- Safari Download Manager; A paid app. Lets you download and save files, even ones that Safari doesn't know how to handle. Great for downloading files and getting them off you phone.
- iFile; A paid app that lets you browse the entire filesystem and open files. Also has a built-in web server that will serve up files to your laptop. Useful when you have no Internet, but need to download a file.
- SysInfoPlus; Shows you lots of technical information about your iPhone. Mostly just neat.
- Status Notifier; shows various status indicators like new mail icon in the iPhones status bar at the top of the screen
- BlackDarkness theme; This is a complete system theme that replaces lots of things, including many icons. I think it's kind of neat. Brings winterboard with it.