If grub is not supported, the following config changes enable systemd-boot
- copy kernel image and initrd out of /boot/ into /tmp
- mount /dev/sda1 on /boot
- copy kernel image and initrd into /boot
- run
# bootctl install - edit /boot/loader/loader.conf:
timeout 5
default debian*- edit /boot/loader/entries/debian.conf
title Debian GNU/Linux
version 4.8.0
linux /vmlinuz-4.8.0-2-amd64
initrd /initrd.img-4.8.0-2-amd64
options root=/dev/sda2 i915.alpha_support=1 rw- run
# bootctl update - set bios password, disable secure boot