Usually I simply run “YaST2 Boot Loader” as default to discover other OS or reorder the current OS first (again) on the Grub2 menu.
This time I changed
Boot Code Options from "GRUB2 for EFI" to "System Boot"
Systemd-boot support is currently work in progress and
may not work as expected. Use at your own risk.
Currently we do not provide official maintenance or support.
Proceed?
<Continue>
<OK>
These packages need to be installed:
sdbootutil
systemd-boot
<Install>
Error
Cannot create systemd-boot menu entry:
Command `[["/usr/bin/sdbootutil", "--verbose", "add-all-kernels"]]`.
Error output: No boot loader entries found.
Config 'root' not found.
install: cannot create regular file '/boot/efi/loader/entries/4d852b3c53d4485581f746b85beddd0a-6.12.8-1-default.conf': No such file or directory
Error: Failed to install bootloader entry
<OK>
An entry for Aeon was added on the Grub2 menu. This caused an error and wouldn’t boot Aeon (yet), and output a console error.
However, as warned: Systemd-boot support is currently work in progress", think this looks promising and might be solved later on…