Excellent tutorial video from Yuneec Europe taking us through an update using Yuneec's Update Pilot app. Note that you must have a reliable internet connection.
If you use this method, commercial operators may wish to tell the ST16s to "Forget" the Wi-Fi connection when you are finished. Simply for basic security reasons. "Disconnecting" will not work, as the tablet will reconnect on its own later.
If you do not wish to connect to the internet and use Update Pilot App, update using the easy micro-card method detailed here.