I didn't change or screen said failed? Read only? Or did you use the flashable zip?
If it's read only error it'd saying. Your kernel isn't unsecure. There is a link to a app that can fix it. It's temporary unless you set it to start at boot.
It allows you to push and pull system files via adb.
Flashing isn't affected by this
Sent from my XT1058 using xda app-developers app