CentOS 7: Failed to set MokListRT: Invalid Parameter

If you have the following error upon startup, do this to make the system bootable again.

Failed to set MokListRT: Invalid Parameter Something has gone seriously wrong: import_mok_state() failed:Invalid Parameter

Either burn a new CentoS disc, make a boot flash drive, or insert the install ISO to your VM. Boot from the disc and once the menu shows up select the following: Advanced -> Rescue -> Troubleshooting -> Rescue media -> and press 1 when prompted.

In the terminal you should now have, run the following commands:

chroot /mnt/sysimage
cd /boot/efi/EFI/centos
cp grubx64.efi shimx64.efi
exit
reboot

After the reboot be sure to exclude shim* and mokutil* from yum updates (so that it can stay at version shim-x64-12-2.el7.x86_64)

echo 'exclude=shim,mokutil' >> /etc/yum.conf
yum update

You should be good to go now. If that does not work try copying CENTOS\GRUBX64.EFI over top of EFI\BOOTX64.EFI in your boot partition.