Post #3 is mine. I do as you say copy folder and etc cp -r /usr/lib/opkg/ /tmp/mountd/disk1_part1 I show it in screen, all file is copy But error is same.
cp -r /usr/lib/opkg/ /tmp/mountd/disk1_part1
Upd. Oh I forget about this: Reset back to: option overlay_root /overlay
Try it tomorrow.