There’s so much going in the jailbreak community right now that users are confused what they should be doing and what should be avoided. A while back, someone released a stashing package for iOS 10.1.1 called YUCCA Utilities that stashes your system to fix the Cydia crash issues and low-storage warnings.
iOS hacker Luca Todesco has warned several times that iOS 10.1.1 jailbreak users should avoid installing the ‘Yucca Utilities’ package and any type of Cydia Substrate enabler. Yet, some users who ignored this warning installed the package and have unsurprisingly faced issues. But the disappointing part is that they start to blame Luca’s jailbreak instead of taking responsibility for the harmful packages they install.
Now Saurik has also issued a warning against the use of this package and states that every iOS 10.1.1 jailbreak user should stay away from it. The package is so “broken” that his only “recommendation” for those who installed it would be to restore their devices to iOS 10.2, but he also states that you wait for Luca to release the iOS 10.2 jailbreak before restoring.
His original statement is as follows:
I am concerned the YUCCA package is so broken the only real recommendation I have is to restore your device to 10.2 (though I’d also recommend waiting until Luca releases a jailbreak and just hope that when that happens iOS 10.2 is still a restorable option).
As for Substrate, I wouldn’t worry too much about anything: I’m pretty certain your “worst case scenario” is to hold down volume up while running a new mach_portal, which will disable Substrate entirely, at which point you can fix any issues you have via Cydia.
Although Luca has warned users to stay away from Cydia Substrate enablers, Saurik says that they are not a big issue as the “worst case scenario” would be to put your device into No Substrate Mode and fix the issues via Cydia.
If you haven’t jailbroken yet, I highly recommend that you wait until Luca releases the iOS 10.2 jailbreak. We don’t know when exactly this will happen but his most recent tweet confirms that he’s working on it.[Source: Reddit]