This took some experimentation. At the time of this Gist creation, could not find all the needed clues on the web.
Is suggested to have and verify SSH access into your Workspace in case of trouble. Otherwise a workspace rebuild might be needed, which takes time and runs the risk of losing data in your root and home volumes that changed since last AWS-initiated backup.
Note one nuance of ssh into a workspace - will need leading domain name prefix such as mydomain\myusername.