Avoiding Ubuntu user creation after new rootfs install

from Host PC connected via usb cable to recovery port of AGX device it is possible to connect to OEM configuration setup, unless there is amonitor connected to AGX with

sudo picocom -b 115200 /dev/ttyACM0

if it doesn’t connect it might be required to reboot AGX & try again
https://docs.nvidia.com/jetson/l4t/index.html#page/Tegra%2520Linux%2520Driver%2520Package%2520Development%2520Guide%2Fflashing.html%23wwpID0E0WB0HA