If you’re a seasoned jailbreaker, then you know not to immediately jump to the next iOS the moment it’s available. You watch and wait, and make sure there’s an appropriate jailbreak for this version before you update. If you’re a newbie, however, you might not be well-versed in how all this goes.
There are two main types of jailbreaks — tethered and untethered. Tethered means you have to connect your device to your computer every time it’s powered off in order to maintain your jailbreak. Untethered means you can reboot at will without having to jack in that cable. If you update before one of these becomes available, then you will lose all of your Cydia apps and tweaks until you can re-jailbreak. (And even then, you may have to start from scratch if you don’t back it all up. More on that below.)
Right now, only a tethered jailbreak exists (Redsn0w 0.9.9b3), and it has only been tested on iOS 5‘s GM version running on the iPhone 4, 3GS, iPad 1 and iPod Touch. Obviously, there were no iPhone 4S devices to test it on yet, and the final release of iOS 5 has only just come out. However, there are expectations that the final version will be jailbroken very soon via an untethered JB. (And, if the rumors are true, they’ll be userland jailbreaks. In other words, it will be along the line of the infamous, idiot-proof JailbreakMe exploit.)
[UPDATE: The new Redsn0w 0.9.9b5 for Mac is available now. It’s a tethered jailbreak for all devices with iOS 5, except for the current iPad 2 and iPhone 4S. Click here for more info.]
If you’re planning to get it, you’ll want to be prepared by backing up everything on your device. iTunes automatically backs up your official apps and data (or you can right-click or control-click on the device in the left sideboard of iTunes, and choose “Back Up”), but if you’re a Cydia fiend, that obviously won’t cover everything.
To back-up jailbreak apps, check out packages like AptBackup, xBackup or PkgBackup. There’s a caveat with this, though: At this point, there are a lot of tweaks and apps that don’t work with iOS 5, so even if you secure everything, it doesn’t mean your favorite tweaks will work. You’ll want to look at the update/change logs for your packages to know for sure. If most of your essentials lack iOS 5 support, you have a tough decision to make: Do without them for now, or hold off entirely on updating until they’re ready. [UPDATE: iOS 5-compatible Cydia apps were compiled into a list, available here.]
And for goodness’ sake, make sure your SHSH blobs are saved! That ECID will be crucial if you want to downgrade back to iOS 4 for any reason (or you want to preserve your baseband for unlocking purposes). You can tell if it has been backed up already by launching Cydia, then seeing if there’s a line at the top of the window starting with “SHSH:”, like this:
If not, you should be able to use Tiny Umbrella to do it once they update it for the final version of iOS 5. (The current version works for 5.0b7 and iOS 5 GM.)
Are you planning to jailbreak iOS 5? What’s your plan of attack? Upgrade the software on your device and just wait for a jailbreak, or will you wait entirely until the exploit’s available? Let us know what you’re planning to do, or if you spot anything else that should go on the list.