ssh root@some_hostname
lsblk # identify boot dev. if boot dev is a raid, this could be repeated on all boot devs.
mount /dev/sdd3 /mnt
-mount_point=/mnt/boot_debiantesting # the subvol i want to chboot to
+mp=/mnt/boot_debiantesting # the subvol i want to chboot to
boot_disk=/dev/sdd
-grub-bios-setup -d $mount_point/grub/i386-pc -s -m $mount_point/grub/device.map $boot_disk
+grub-bios-setup -d $mp/grub/i386-pc -s -m $mp/grub/device.map $boot_disk
reboot
todo: figure out if it's possible to make a multi-distro grub like I have with libreboot