Sorry for the delay. We just returned to work after a 5-day national holiday.
This line indicates you are still running Android bootloader, which is not compatible with Linux. Try sudo boot-g12.py radxa-zero-erase-emmc.bin again, and after the program is finished, wait for additional 10 seconds for the code to run in your board. You should be able to lsblk and find a new USB storage device. You can then flash Linux images to it.