Heads has many boot comparability issues:
- NixOS does not boot · Issue #1001 · linuxboot/heads · GitHub
- Debian/Tails doesn't pack exfat support under its initramfs: Heads cannot boot tails iso from exfat partition (upstream issue) · Issue #1810 · linuxboot/heads · GitHub
- Manjaro and Garuda ISOs won't boot automatically · Issue #1605 · linuxboot/heads · GitHub
- Guixsd/Proxmox installer wont boot issue · Issue #750 · linuxboot/heads · GitHub
- Booting Arch Linux · Issue #702 · linuxboot/heads · GitHub
- Kexec-parse-boot can't handle arch install usb · Issue #584 · linuxboot/heads · GitHub
heads is:
- kexec based
- parsing
grub.cfg. - Heads became grub centric · Issue #1918 · linuxboot/heads · GitHub
I don’t like this workaround because it hooks into the initrd generation process and adds more complexity.
Quote initrd/kernel packed in ISO doesn't support exfat (#20621) · Issues · tails / tails · GitLab
Also, I would like to raise concerns on often changing used distro signing key, which is really fast paced for Heads downstream forks which provide 1 release a year (and your distro signing key that will expire in 272 days, which will cause problems for next firmware releases validating iso against detached signature and distro key fused in firmware).