Thank you DaveYYY and linuxdev, your help is much appreciated.
linuxdev said
…then you must revert back to the NVIDIA provided Ubuntu 18.04…
No need to revert, I have dual boot here, the 18.04 provided by NVIDIA is still bootable on the 16 GB eMMC, and I can boot the 20.04 QEngineering image from the NVME SSD. The best of both worlds!
The NVIDIA image boots fine (using uboot through the serial interface), and the GUI loads, so nothing wrong there.
linuxdev, thanks for the detailed notes on HDMI and DVI. I’m not sure I understand it all, but I get two messages that may be relevant:
tegra-i2c 7000c000.i2c: no acknowledge from address 0x50
and identical text but with the address 7000c400.i2c
As an experiment I tried booting the QEngineering image without the HDMI cable in, and put it in once it had booted. I got output saying
edid invalid
three times in a row, I think this may be what you’re talking about.
Would there be a reason why the NVIDIA image would be able to use the HDMI>DVI connection, but the QEngineering image can’t?