Update: Saurik said that this update is not fixing the issue. Lots of users have cydia crashing after this update.
OK, so this is a pretty serious issue: the new patch that TaiG built just doesn’t work :/. I wish they would calm down and let me do this correctly. I’ve pulled their update.
How to downgrade to TaiG 2.2.0
I have downgraded to TaiG version 2.2.0 – please note that I`m not sure if this is recommended. Do it on your own risk:
Download http://apt.saurik.com//debs/taiguntether83x_2.2.0_iphoneos-arm.deb and install it with iFile. Make sure you close cydia first. After this, you should have the older version of TaiG untethered (2.2.0).
As we already told you, TaiG had a big security flaw that allowed any app to get root access, so they just released TaiG version 2.2.1, claiming this was fixed.
Fixes setreuid patch to prevent applications from obtaining to root privileges through setreuid.
When updating from cydia, my iPhone started to reboot and show up some blue screens, while rebooting again. I thought it went into a reboot loop and got scared for a while. After a few restarts, all went back to normal. Seems that this is not an isolated case.
— BestCydiaTweaks (@BestCydiaTweaks) July 2, 2015