Just built an flashed an own Yocto image to Edison and was puzzled I couldn't ssh in the box over ethernet.
It took me a while to realize that /lib/systemd/system/sshd.socket was preventing it by the
setting - which was generated by the unmodified Yocto recipes. Not sure why it didn't work as I'm connected by an USB ethernet dongle.
However, after commenting this line ssh'ing in worked fine
Retrieving data ...