[CentOS] EFI boot order rewrite

Thu Feb 23 12:48:58 UTC 2023
Florian Bauer <florian at fsrv.xyz>


we are running CentOS Stream 8 on some of our dedicated servers.
On the newer servers that boot with efi, the system that is installed 
with the default properties in the ISO installer writes itself to the 
top of the efi boot order.
This seems to happen every time after bootup.

Since we run all our systems with efi network boot as the first boot 
option for rescue operation, this would be a significant problem for the 
future if the behavior cannot be turned off.

I have already checked the use of efibootmgr and some of the related 
grub settings such as GRUB_DEFAULT and GRUB_SAVEDEFAULT (which may have 
nothing to do with it).
On Debian, I found a debconf option that prevents updating nvram.
This seems to prevent the described behavior.

Does anyone have an idea for this problem?

With kind regards