Flashing with ethernet cable is also supported, but you need to know the IP address in advance, and the ethernet cable is only effective after the device boots into initrd, and you still need a USB cable for the flashing process prior to it.
Cropped from Linux_for_Tegra/tools/kernel_flash/README_initrd_flash.txt
- Use --network <netargs> if you want the flash process to happen through Ethernet protocol
instead of USB protocol. Ethernet protocol is more reliable than USB protocol
for external devices like USB.
<netargs> can be "usb0" when flashing using ethernet protocol through the usb
flashing cable or "eth0:<target-ip>/<subnet>:<host-ip>" when flashing using
ethernet protocol through the RJ45 cable.