USB-C Hub Ethernet Not Working

Question

Today I installed Ubuntu 18.04.3 on a Google Pixel Chromebook (2015) using the MrChromebox firmware script. The installation went well but there seems to be a problem with my USB-C Hub with ethernet adapter. Ubuntu is not recognizing the ethernet port on the adapter. I know it works because, before I installed Ubuntu, I tried it on ChromeOS.

Any advice on getting Ubuntu to recognize the ethernet port on this USB-C adapter?

Thank you!

Edit: output of lsusb command as recommended by @telcoM:

With USB-C Hub disconnected:

Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 005: ID 8087:07dc Intel Corp. 
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

With USB-C Hub connected:

Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 005: ID 8087:07dc Intel Corp. 
Bus 001 Device 013: ID 1d5c:7102  
Bus 001 Device 012: ID 1a40:0801 Terminus Technology Inc. 
Bus 001 Device 011: ID 05e3:0610 Genesys Logic, Inc. 4-port hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Answer 1

Partial answer:

If you look only at the additional devices as suggested in the comment, you see

Bus 001 Device 011: ID 05e3:0610 Genesys Logic, Inc. 4-port hub

a 4-port hub, and on this hub two devices

Bus 001 Device 012: ID 1a40:0801 Terminus Technology Inc. 
Bus 001 Device 013: ID 1d5c:7102

with no further information. From your Amazon link, your "hub" includes a HDMI device, a card reader, and the ethernet adapter.

So we must somehow find out which of those two listed USB devices corresponds to which of the three devices you should have. (Guess: The HDMI device probably uses alternate mode, so it's the other two).

You can do that either by lsusb -v -d 1a40:0801 and lsusb -v -d 1d5c:7102, which should give you the class, or by looking at dmesg after you plug in the hub, and the kernel hopefully identifies the card reader. (If you don't know how to interpret the dmesg output, please include it in your question. You can indent four spaces for pre-formatted text like log outputs.)

Normally googling for 1a40:0801 and 1d5c:7102 can be used to get more information, but in both cases I couldn't find anything.

The most likely case is that your Ubuntu is for some reason missing the kernel drivers needed for the USB ethernet adapter.