Solusion for overlayroot in Armbian Jessie:
1) install overlayroot_0.27ubuntu1.4_all.deb
dpkg -i overlayroot_0.27ubuntu1.4_all.deb
2) add following lines to /usr/share/initramfs-tools/hooks/overlayroot file:
copy_exec /bin/grep /bin
copy_exec /usr/bin/stat /bin
copy_exec /bin/echo /bin
This will load missing tools required by /usr/share/initramfs-tools/scripts/init-bottom/overlayroot script.
3) replace all "mount --move" with "mount -o move" in /usr/share/initramfs-tools/scripts/init-bottom/overlayroot file.
4) update-initramfs -u
:-)
overlayroot_0.27ubuntu1.4_all.deb
