I may have found the answer:
#HEX S RB760iGS → console mode…?
[http://forum.mikrotik.com/t/hex-s-rb760igs-console-mode/131826/4]
You can use USB to serial adapter for console, however console will not be spawned on it by default.
So in case where you already have inaccessible device (like after FW misconfiguration) you can’t just plug in USB to serial cable and get console, it has to be first configured to run like that.
WOOBM is probably special in some way where ROS automatically spawns new console on it by default (probably using VID/PID or some other ID).