Thank you for the suggestion. I've updated the patch and attached it.
*** /tmp/10_linux.orig 2017-02-02 08:02:36.926542777 -0700
--- /etc/grub.d/10_linux 2017-02-02 15:26:02.138285042 -0700
***************
*** 77,85 ****
GRUB_CMDLINE_LINUX="rootflags=subvol=${rootsubvol} ${GRUB_CMDLINE_LINUX}"
fi;;
xzfs)
! rpool=`${grub_probe} --device ${GRUB_DEVICE} --target=fs_label 2>/dev/null || true`
! bootfs="`make_system_path_relative_to_its_root / | sed -e "s,@$,,"`"
! LINUX_ROOT_DEVICE="ZFS=${rpool}${bootfs}"
;;
esac
--- 77,96 ----
GRUB_CMDLINE_LINUX="rootflags=subvol=${rootsubvol} ${GRUB_CMDLINE_LINUX}"
fi;;
xzfs)
! zfsbootfs=`zpool get bootfs | sed '2,100!d' | grep -v '\s-' | awk {'print $3'} 2>/dev/null || true`
! if [ "${zfsbootfs}" = "" ]
! then
! echo "zpool bootfs parameter not set. System will fail to boot!" 1>&2
! elif [ "$(echo ${zfsbootfs} | wc -w)" -gt "1" ]
! then
! echo "Multiple zpool bootfs parameters detected:" 1>&2
! echo ${zfsbootfs} 1>&2
! echo 1>&2
! zfsbootfs=`echo ${zfsbootfs} | awk {'print $1'}`
! echo "Using the first bootfs listed: ${zfsbootfs}" 1>&2
! echo "Final LINUX_ROOT_DEVICE=ZFS=${zfsbootfs}" 1>&2
! fi
! LINUX_ROOT_DEVICE="ZFS=${zfsbootfs}"
;;
esac
