Woo!
root@OpenWrt:~# df -k
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/root 5888 5888 0 100% /rom
tmpfs 1020704 72 1020632 0% /tmp
/dev/mmcblk0p66 7327000 187784 7139216 3% /overlay
overlayfs:/overlay 7327000 187784 7139216 3% /
tmpfs 512 0 512 0% /dev
Works!
Thank you!