When bundled Zebra starts it says "su/sling does not have permission to set the uid or gid. Please verify the permissions of the file located at /usr/libexec/zebra/supersling." so I cannot update Zebra or install Filza to fix permissions.
I tried respringing, rebooting, and resetting all settings, but none helped.
P.S. Zebra update should be disabled on iOS 9-10, where the modified build is used.