Comment # 66 on bug 1226122 from Mario Guzman

After a few days testing I got RefindPlus to boot Systemd-boot into Tumbleweed.
The most important change needed to Tumbleweed systemd-boot is to provide an
option to not update nvram/mbr as Grub2 has. The following three methods booted
from RefindPlus with no RP configuration required:

1. Install TW - systemd-boot
I created an ESP partition for each TW OS partition. TW installed boot code
into the new ESP and TW booted normally. This method requires a separate ESP
since it would overwrite the active ESP boot code, that’s acceptable since I
understand it’s needed to support snapshots, encryption, etc. By having a
separate ESP for each OS system multiboot can be maintained with not too much
extra effort, just an extra partition for each linux OS. This method left /boot
empty but booted fine so empty /boot was fine.

However, I had to use efibootmgr -o to reset the default boot loader. That
would not be required if TW had the option to not modify nvram/mbr. The good
news is that since the original ESP containing RefindPlus and OpenCore managers
was not touched, the efibootmgr command was all that was needed to get back to
normal booting.

2. Install TW - Grub2
Exactly the same as systemd-boot except I had the options to turn off update
nvram/mbr. That meant after TW installed Refind was still intact as the default
boot manager. This method populated /boot.

3. Install TW - No Boot Manager
This can be done but adding “suse-module-tools-scriptlets” to the software
selection. This will populate /boot to make it bootable. I understand this is
not the future though.

So it if systemd-boot is the future and it can be booted from a different boot
manager, we need the option to not update nvram/mbr to make the installation
simpler. Hope you consider that since it seems more compatible with the future
of removing /boot.