Is systemd-boot supported or not?

[chlorodose]

Install with bootc install to-disk --bootloader systemd <disk> will report error: Installing to disk: bootupd is required for ostree-based installs. I tried with fedora-bootc:rawhide and my own image with dnf swap bootupd systemd-boot.

Dose that means only grub is supported without --composefs-backend? I'm really confused because this error only report after parting the disks(bad options should report just after the command is started right?) and the docs seems to say that systemd-boot is always supported

[Johan-Liebert1]

It's currently only supported for composefs backend, not for ostree. The docs did not mention this fact