Ok, I finally narrowed down the problem. I tried everything with Debian Stretch and it was fine. I then tried again with Debian Testing/Buster netinst and it was broken. I tried again with a Debian Testing/Buster DVD instead of netinst and it worked. The problem turned out to be with systemd. The latest systemd in Debian Testing right now is 236-2, which is what the netinst installed. Stretch and the Testing DVD installed systemd 235-3 worked. I noticed Debian Unstable/Sid is on systemd 236-3 so I installed again, using Debian Testing/Buster netinst, then upgraded systemd from 236-2 to sid's 236-3 and it worked. So, I guess we can close this thread and I'll go find the Debian Testing systemd guys..
Thanks to everyone who took the time to read this thread & offer help/suggestions!
(more info on the offending bug is here:
https://bugs.debian.org/cgi-bin/bugr...cgi?bug=885325)
