Robin Klitscher composed on 2020-10-28 12:58 (UTC+1300):
1. On all three installations the line in etc/default/grub is empty, as in "GRUB_DISTRIBUTOR= ". Since this includes the 15.2-1 installation that works, I wonder if the steps you outline in that regard are strictly required?
By default, "GRUB_DISTRIBUTOR= " translates to /boot/efi/EFI/opensuse. Last installation to write it wins control of the post-Grub boot process. All mine get a unique one first thing after installation, or even before if I'm particularly ambitious, with the result that I can safely delete any "opensuse" directory on the ESP filesystem. Mine unambiguously include opensusetw, opensuse423, opensuse150, opensuse151, opensuse152, fedora32, fedora33, debian10 and debian11, so none overwrite others, and with mounting the ESP partition *only* to the installation I wish to control booting as I do, booting never gets broken unless I screw something up myself, or forget first thing with a new installation to undo. I usually don't need to undo it, as I usually remember to taboo Grub installation unless it's the first on a new ESP. -- Evolution as taught in public schools, like religion, is based on faith, not on science. Team OS/2 ** Reg. Linux User #211409 ** a11y rocks! Felix Miata *** http://fm.no-ip.com/ -- To unsubscribe, e-mail: opensuse-support+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-support+owner@opensuse.org