On 1/11/19 3:22 AM, Gary Stainburn wrote: > I then installed grub2 on sdb > > yum install yum install grub2-efi-modules > grub2-install /dev/sdb If you want to manually provide redundant EFI system partitions (no RAID1), all you need to do is run efibootmgr to add a second entry. You don't need to install grub2-efi-modules or run grub2-install. Use: efibootmgr -c -w -L 'CentOS Linux' -d /dev/sdb -p 1 -l 'EFI\centos\shim.efi' ... where the option to -d is the name of the drive containing the EFI system partition and the option to -p is the EFI system partition number. For reference, that command will appear in /var/log/anaconda/program.log after any normal installation.