MacOS – Does the USB-C Digital AV Multiport Adapter transmit 4K 60Hz signal from M1 MBP

Yes - Macs have internet sharing where you can use one device to get internet and share it from another.

Most people in a cabin situation set up an AirPort to let all the devices talk and then you would share from the USB to the physical ethernet port. The router would get to the internet from the ethernet and everyone can join the WiFi and share whether or not the USB modem is dialed.

You would set the service order to have the USB modem be the highest connection in the network pane.

What you ask is also possible - just share from USB to WiFi and the Mac will create a wireless network the other devices can join.

For those searching I am having this issue with a new 2016 MacBook Pro running sierra v10.12.1. Multiple Install->Reboot cycles with everything still plugged in but the Multiport Update is not being installed.

[RESOLVED]

UPDATE: Your USB-C Power Cord must be plugged directly into your multiport adapter (which is plugged into your laptop) when doing the reboot. Having the adapter plugged into one port, while the power cord is plugged into another of your laptop's ports will not work.

NOTE 1: Working Layout

Wall power outlet => USB-C Power Adapter => USB-C Power Cord => Multiport Adapter => Laptop (You don't need the external display plugged in.)

NOTE 2: When I first plugged my power cord into the multiport adapter, it displayed some weird behavior where the Driver Install prompt went away and the "charging" icon would show briefly, then disappear. I restarted my laptop with everything still plugged in and then the Driver Install prompt stayed visible.

You could probably also click the "Install" button before pluggin in the power cord and once the wizard is open, plug in the power cord. I'd guess the power cord is only required to be plugged into the multiport adapter to give the adapter power during the reboot.

NOTE 3: The time that the install/reboot actually worked, the reboot took a significantly longer time than usual. Probably about 3 mins. So if you also experience that then its a good sign.