The Gnome desktop Power off menu selection and `sudo shutdown now` both reboot rather than powering down.

yeah, frustration is quite clear, but probably it is manufacturer who should be most/only interested in that. that also cost quite a lot, so it is probably better to demand where money were paid to, i guess.

That is the expected behavior. You always need to "install" u-boot after a new version from apt. The apt package just provides the binaries that you can install.

Tried rk3318 debian 12 with linux kernel 6.1.63 or up to 6.12.39 and no hdmi output, I installed on SD card. Though debian 11 with kernel 5.15.35 works Interesting thing that debian 12 with linux kernel 6.16.0-rc3 worked Is there anything I can do to provide useful information to debug?

At the same time as mmcblk1 disappeared someone had changed the ethernet port over to the secondary port as I could not get into the machine and tried the second port which had been configured to the same static IP address as the primary port was on.