Cable Matters has released a firmware update to resolve a compatibility issue with the Amazon Fire TV Stick 4K Max.
This firmware update applies to the following Cable Matters product:
This firmware update resolves the following issues:
1) Download the Firmware and Update Tool here, and unzip the folder.
2) Connect your computer to a power supply
3) Connect the Micro USB Ethernet Adapter to your computer using a USB-C to Micro USB Adapter
4) Connect the Ethernet Adapter's USB-A connector to your computer or USB power outlet
5) Double-click on "RtPGtoolUI.exe" to open the tool
6) Click the "Dump" button 
7) Make sure the "Fix MacAddress" box is checked 
8) Change the last digit of EXT_PATCH to "4" 
9) Click on "Program" 
10) Wait for the result to be "Pass" 
11) Power cycle the adapter by removing both connectors, and then reconnecting them
12) Click on "Dump" and verify that EXT_PATCH is flashed to 00000004