BBB Set Up to Network Boot on Ubuntu 18.04

[leo.e...@gmail.com]

I'm trying to setup network boot per this wiki:

http://software-dl.ti.com/processor-sdk-linux/esd/docs/latest/linux/How_to_Guides/Host/How_to_Setup_Ubuntu_1404_Network_Boot.html

I'm using the USB0 method, so I'm using step #9 instead of step #8.

However, my host PC is Ubuntu 18.04.

When I boot the BBB, while pressing the boot button, no SD card inserted, all I see on minicom is:
CCCCCCCCCCCCCCCCCCCCCCCCCCCC

I can't tell if these instructions are simply not valid for Ubuntu 18.04, or if I'm doing something wrong. Any advice or suggestions greatly appreciated.