Fix corrupt etc files stopping system from booting
From Pengwings
This is a dangerous last resort option
Boot into the previous deployment from grub
Remount sysroot as read-write
sudo mount -o remount,rw /sysroot
Find the directory
cd /sysroot/ostree/deploy/default/deploy/ ls -alF
Go to the broken file inside the borked deployment and fix it
Reboot