Now that iOS 5.1 has been released, the iPhone Dev Team has released a new version of redsn0w to allows users to perform a tethered jailbreak on it. Although a tethered jailbreak isn’t the most desirable route to take (and isn’t compatible with all iDevices), at least some users who have updated to the new iOS version will still have the option.
The only iDevice lucky enough to enjoy an untethered jailbreak on iOS 5.1 at this point is the old bootrom iPhone 3GS, while the iPad 2, iPhone 4S, and third-generation iPad are all completely unsupported. The iPad 2 and iPhone 4S will also no longer be able to downgrade to iOS 5.0.1 once Apple stops signing the firmware, which is expected to be quite soon. Therefore, if you value the untethered jailbreak that’s possible on iOS 5.0.1, it is a good idea to avoid updating to 5.1 altogether or to downgrade now while you still can.
Users relying on an unlock wishing to install iOS 5.1 are advised to create a custom NO_BB_* IPSW in redsn0w 0.9.10b6 to restore to in order to prevent a baseband update that would compromise the ability to unlock now and possibly in the future as well. The iPhone Dev Team plans to update ultrasn0w within the next few days in order to support unlocking on iOS 5.1.
Users dependent on iBooks functionality should also be aware that jailbreaking will take that away, as there is no iBooks fix for iOS 5.1 as there is on 5.0.1.
If you’re running iOS 5.1 and interested in a tethered jailbreak, or if you’d just like to update redsn0w to the v0.9.10b6, you can read the release notes and download it for OS X and Windows from the iPhone Dev Team’s blog post.