On freshly flashed rut240 (from 1.11.3 to 1.14) the above instructions didn't work.
On my router ncurses are version 6, not 5, so it needed TWO symlinks: summarizing
opkg update
opkg install nano
and then
ln -s /usr/lib/libncurses.so /usr/lib/libncurses.so.5
ln -s /usr/lib/libncurses.so.6 /usr/lib/libncurses.so
Hope this helps.