Apple released a software update for iPhone, iPod touch and iPad today. The update changes the way iOS devices save location data — but as with most iOS updates, if you upgrade a jailbroken device you’ll lose your jailbreak.
It turns out that you can use redsn0w to re-jailbreak your device after upgrading. The only catch is you’ll end up with a tethered jailbreak, which means you’ll need to plug your iOS device into a computer every time you reboot or you’ll lose your jailbreak. But it’s better than nothing.
It’s possible that new jailbreak tools will be available soon, offering untethered access though, so you might want to hold off. And if your phone is carrier unlocked, you should probably wait for a new version of ultrasn0w.
In the meantime, you can find my step-by-step instructions for jailbreaking using redsn0w 0.9.6.