Thanks, I really appreciate your help. I need one more detail so I can test. How do I include the makefile you wrote into the firmware build?

I’ve downloaded GitHub - gl-inet/lede-17.01: Cloning from https://git.lede-project.org/?p=source.git;a=summary and adding patches for GL's new devices to lede-17.01.
followed instructions here Overview - GL.iNet Docs to build the toolchain, sdk, image builder, and select the nand target, that build was successful.
Found the libusb-compat package and added it to my .config.
Confirmed I was able to generate firmware compatible with my hardware.
Updated and downloaded the feeds which brought in gli-pub/teensyloader at master · gl-inet/gli-pub · GitHub
However, I cannot find the teensyloader package in menuconfig. How do I select it to add to the firmware build.

I’m sure it is very simple and probably explained somewhere, but after 2 days searching I still haven’t found it. Me feeling really dumb right now, but very grateful.

edit: Yes, I am trying to run teensy_loader_cli on AR300M. It is used to load a precompiled .elf file onto an Arduino compatible called Teensy which has a different bootloader than other Arduinos. If this works, we will next be able to port over GitHub - PaulStoffregen/BridgeUSB which will complete a journey started at Combining teensies with the Arduino Yun to make a better 2 piece Arduino Yun