If you haven’t upgraded your jailbroken iOS device to iOS 5.1 then please read this post as it could just save you from restoring your device if something goes terribly wrong due to problematic jailbreak app or tweak.
While we eagerly wait for the jailbreak community to release an untethered jailbreak for iPhone 4, iPhone 3GS, iPad 1, iPod touch 4 and iPod touch 3 and a jailbreak for iPhone 4S, iPad 2 and iPad 3, there is always a risk that a jailbreak tweak can mess things up that could force you to restore your iOS device, which means you also end up losing the jailbreak.
Jay Freeman aka saurik has just released a new version of Mobile Substrate that could save the day for you. Mobile Substrate 0.9.3997 now allows you to disable Substrate entirely by holding down Volume Up button as the device reboots. saurik explains:
This feature allows you to bypass horribly broken extensions (ones that prevent the device from starting up at all) that you may have installed so you can open Cydia and uninstall them.
To support devices that do not have a Volume Up button (the first-generation iPod touch), you can alternatively hold down the “Clicker” (not Volume Up) button on your headset or earphones.
So if you’ve a jailbroken iOS device running iOS 5.0.1 or lower then don’t waste any time and install the Mobile Substrate update via the Changes tab in Cydia to avoid restoring your jailbroken iOS device after installing a problematic jailbreak app or tweak.
Please be extremely careful before installing new jailbreak apps or tweaks and it is also a good idea to check reviews of the jailbreak app or tweak before installing it, which usually result in your iOS device getting stuck in a boot loop.
Thanks Chris for the tip!