Apple USB-C Multiport adapter bricked I purchased a USB-C Multiport adapter and plugged it into my new MacBook Pro.  Immediately I was told to upgrade the adapter, and I clicked okay and then right through the usual installer screens.  Installation finished, I clicked reboot and one of my Applications cancelled the restart.  I quit that app manually and then rebooted.  MacBook rebooted, but adapter doesn't work and the upgrade nag no longer shows up.

I understand now that it's important to plug the power into the slot on the adapter (rather than into your MacBook) when doing the upgrade, and it's a good idea to read the installer ReadMe, but this was not done.

Opening /System/Library/CoreServices/Firmware\ Updates/USB-C\ Multiport\ Adapter/adapterupdate1.pkg and trying to re-run the upgrader manually fails with the message: "This software is not supported on your system".

System Report seems to recognize the USB Multiport adapter, and see's version 2.33, however any devices plugged into the adapter (HDMI, USB) while they register in system report, don't actually work.

This is the second adapter that I did this too so I'm pretty sure the issue was related to not being plugged in during the upgrade, but surely there is some way to reset / re-image the damn thing, I'd rather not get a 4th one.
Your adapter is not bricked per se. I have two of them and have been unable to get them to work at all under Sierra 10.12.6 using HDMI. I was able to update them both and reboot successfully. They both show up under System Information as you describe, but no connection is ever established with the HDMI display.

Failing the reboot of the computer is not the problem. It's just that the reboot is needed before the system will recognize it. If you have rebooted since then, you have done all that you can do. I have thought about reaching out to Apple Support, but feel it is going to quickly become a wild goose chase with them.