Are you using systemd-boot?
Oops, I believe that package never made it out of development and should be considered abandoned:
This command is not specific enough to be run as-is on a Garuda LInux system. At the very least, you would need to add arguments for the path of the initramfs, and the naming convention it should follow.
Garuda Linux has a special command for rebuilding the initramfs, which is tied in to a bunch of custom hooks and scripts:
sudo dracut-rebuild