Thanks for the compass heading grn.
While building an Armbian image looks like a good learning project for me and I may do it just for the experience some day, the truth is all this time I've been trying to avoid deploying a fresh image to my existing SBC. I was hoping to somehow modify the existing configuration to "not break" when updates were applied. I guess that's a pipe dream and I should get off my butt and re-deploy Armbian, one way or another.
My thanks and regards to all who chimed in on this saga.