bootctl does not support installation on a dos/mbr partitioned disk #1125
I have a very strange Dell laptop with a UEFI firmware which does not support GUID partition tables (GPT). It does support running EFI binaries, and it will detect an ESP on an MBR-style disk (a partition with type id 0xEF).
When I attempt to install systemd-boot using bootctl, it complains that my /boot file system does not reside on a GPT partitoned disk.
systemd-boot works just fine on this system if I manually copy the binary to the ESP.
Anyway there is a firmware bug in the wild where BIOSes and EFIs require that at least one hard disk have at least one MBR partition that's marked as bootable/active to boot. Since the protective MBR's single EFI GPT (0xEE) partition is not normally flagged in this way, the affected firmware won't boot from GPT disk ( you can install using GPT partitioning in any *nix distribution but you wont be able to boot which fails with "BootDevice not found" ) so you might need to flag it as such, to be able to use GPT with that firmware ( parted /dev/sd disk_set pmbr_boot on I believe ) and that might be the underlying root cause for your problem. It would be good to know if you try this if things work for you or not. ( as in you can use GPT and bootctl works accordingly afterwards )