I got it. After my previous message, I decided to chase down the thread that it doesn't work even when I'm not booting to X, thinking that might be a simpler setup and easier to debug.
Once I turned "quiet" off, I saw the last message printed was: fb0: switching to nouveaufb from EFI VGA Okay, clearly that switch was not successful and it gave me something new to Google. One suggestion I found was to try setting nomodeset which did allow me to continue the boot to a login prompt but then I couldn't run startx. Eventually I found in dmesg that it was failing to load gp107/sw_nonctx.bin. Searching for that, I found that it lives in firmware-misc-nonfree. Once I installed that package, everything got much better. Thanks for all your help. Dave
