CentOS7 Xen grub2 can’t find command multiboot – solution

Ok so you have a fresh installation of CentOS7 were following the CentOS Xen quick start and you have an EFI BIOS and you’re unable to boot the Xen kernel.

This is how it’s fixed:
You boot from any other kernel and login, etc..

Then edit /boot/efi/EFI/centos/grub.cfg (with nano, vi, vim or whatever)
Right below the menuentry that starts with

you add an

so that your file looks like

You will however have to do this every time a new grub.cfg is generated
I find grub2 complicated and have not found a way to add this line so it gets created automatically every time a grub.cfg is generated.