[CentOS] CentOS6: HELP! EFI boot fails after replacing disks...

Tue May 29 03:54:32 UTC 2018
Gordon Messmer <gordon.messmer at gmail.com>

On 05/28/2018 06:58 PM, Robert Heller wrote:
> At Mon, 28 May 2018 18:23:42 -0700 CentOS mailing list <centos at centos.org> wrote:
>> On 05/28/2018 03:25 PM, Robert Heller wrote:
>>> I tried to run efibootmgr, but it wants a model named efivars loaded, but
>>> there is no such module available.
> newserver.wendellfreelibrary.org% sudo efibootmgr
> [sudo] password for heller:
> Fatal: Couldn't open either sysfs or procfs directories for accessing EFI variables.
> Try 'modprobe efivars' as root.
> newserver.wendellfreelibrary.org% sudo  modprobe efivars
> FATAL: Module efivars not found.
> newserver.wendellfreelibrary.org% dmesg | grep efi:
> newserver.wendellfreelibrary.org% ls /sys/firmware/efi/
> ls: cannot access /sys/firmware/efi/: No such file or directory
> newserver.wendellfreelibrary.org% uname -a
> Linux newserver.wendellfreelibrary.org 2.6.32-696.28.1.el6.x86_64 #1 SMP Wed
> May 9 23:09:02 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
> newserver.wendellfreelibrary.org%

Look into the possibility that you're booting via BIOS and not UEFI.

It's possible to have /boot and /boot/efi, and also to have GRUB2 
installed on the disk, in which case the system is able to boot from 
both BIOS and UEFI.

If that's the case, then you'd need to install GRUB2 on the new disk as