Background: Pi 3 B+ connected to an old tube TV with front composite video connection.
I've installed NOOBS on a 32GB microSD card, and am able to successfully boot it, using the keyboard 4 key (NTSC) to display the graphical installer.  After the install finishes and the Pi boots, I can no longer get any video to display.
I have set sdtv_mode=0 and hdmi_ignore_hotplug=0 in the config.txt on the /boot partition of the SD card.
