Actually not yet too successful booting my #BuildRoot image with systemd-boot. With grub-efi I got to the login.
EDIT: I think I got it and it is pretty obvious. I’m still deploying GRUB style configs when I construct the disk image with genimage, so I just fix them up as systemd boot style configs (found a reference for that).
So I just follow along [1] and cross my fingers ;-) I think it is good exercise to build from scratch a systemd image from boot to user space in all cases.
[1] https://www.freedesktop.org/wiki/Software/systemd/systemd-boot/
Right this tells me everything:
$ fatcat efi-part.vfat -x tmp
Extracting /EFI/BOOT/BOOTX64.EFI to tmp/EFI/BOOT/BOOTX64.EFI
Extracting /bzImage to tmp/bzImage
I don’t know if there is any more modern tool for this but this is sometimes useful: https://github.com/Gregwar/fatcat
Looking of surface better:
Extracting /EFI/BOOT/BOOTX64.EFI to tmp/EFI/BOOT/BOOTX64.EFI
Extracting /bzImage to tmp/bzImage
Extracting /LOADER/loader.conf to tmp/LOADER/loader.conf
Extracting /LOADER/ENTRIES/buildroot.conf to tmp/LOADER/ENTRIES/buildroot.conf