Does this run on Odroid C2? I can supply UART output if you need.
Yes, this is possible. View this topic. It describes how you can easily add to the existing system on the SD card or eMMC module on the Odroid C2, the ability to run from USB. Or easily transfer run from eMMC to SD card without pulling the module eMMC (or Vice versa). Pay attention that the current system on the SD card or eMMC module as not changed. Ie. if connected USB flash drive is the launch of the system from it (it can be any system - any option Libreelec or Linux). If you disable USB flash drive will automatically start the "internal" system on the SD or eMMC. If not clear, ask, I work a different system on Odroid C2 in various combinations (USB SD).
Odroid C2 Temporary run images from USB - Amlogic - Armbian forum
i test sdcard and usb
I see you have the UART console and in the log there is an indication that your u-boot has the ability to use the script "boot.ini" is good. Show the output of "printenv" and "help" (you need to stop the run u-boot by pressing spacebar and execute these commands).