Unable to Boot from USB / Unable to keep OS persistent

I’ve been trying to set up my La Frite for some light home-network services. For the life of me I wasn’t able to flash an OS from a USB, but was able to download Debian via EtheralOS steps when connected over Ethernet.

This didn’t actually fix my problem though, as when I had to turn off power to the board, I ran back into the the issue where it can’t boot from the USB, so the server set up can’t load. Any advice beyond getting the only eMMC in stock would be appreciated. UEFI output included