[CentOS] CentOS 7 1708 won't boot after grub2 update

> 
> No gray 7-boot screen. Might be a graphics issue, the card is a Nvidia 1060 with no particular drivers loaded except for the default Nouveau package.
> What's weird is that I can't even get a CLI login screen with ctrl-alt-Fx at this point.
> 
> Will continue trouble-shooting and see if I can resolve this properly.
> 

Edit the grub line to boot into single user and remove "rhgb" and
"quiet" so you can see all the messages. See where it stops.

I've seen issues recently with Intel chipset and RAID - a couple of my
machines have paused for a very long time after booting and before
presenting login screens/prompts. It looks as if checking the array
after a non-clean shutdown is sucking so much CPU time that nothing
else happens. (The secondary issue is why it's shutting down without
marking the array as clean!)

P.