Once upon a time, Brian Mathis brian.mathis+centos@betteradmin.com said:
if grep -q debug /proc/cmdline; then echo "Kernel and systemd debugging was enabled as part of an errant script during the yum update" echo "See https://bugs.centos.org/view.php?id=12425 and https://wiki.centos.org/HowTos/Grub2" fi
Assuming your GRUB entries are in the usual order (newest kernel first), you can do:
grub2-set-default "$(grep '^menuentry' /boot/grub2/grub.cfg | grep -v debug | head -n 1 | cut -d' -f2)"
and then reboot.