Hi,

this follows https://progress.opensuse.org/issues/162401.

Background:
We have several hypervisors with a software RAID (MDADM) setup, which also
houses /boot and /boot/efi. This always worked very well on Supermicro
platforms and avoided the need for additional tricks to keep the EFI partition
redundant and in sync.

Situation:
The upgrade to 15.6 on one such machine (with a Supermicro H12SSL-NT board)
worked fine.
A second machine (with a Supermicro H12DSi-NT6 board) however freezes at POST
during the reboot while printing "Ready to boot" (after which it would usually
execute to the OS bootloader) after the 15.6 upgrade.

Entering a chroot from a live environment, downgrading the GRUB packages to the
ones used on 15.5

grub2-2.06-150500.29.25.12.x86_64.rpm
grub2-i386-pc-2.06-150500.29.25.12.noarch.rpm
grub2-x86_64-efi-2.06-150500.29.25.12.noarch.rpm

and `bash -x /usr/lib/bootloader/grub2-efi/install` makes the machine boot
again.

Advice would be appreciated - we have several more of the H12DSi-NT6 machines
which we cannot upgrade to 15.6 because of this.