Board image

yes, i've studied the schematic well to see if that gave any clues and I have learned that it ties into the Power Management Unit. It remains that the button doesn't work on mainline kernels but does on the vendor kernel. There must be some init step or configuration that's missing.

https://docs.armbian.com/User-Guide_Armbian-Config/System/#desktop Should be straighforward to enable desktop on top of CLI.

Hi Gentleman, all desktop images disappeared for Opi 3B. Is there a chance that will be available later?

According to the circuit diagram, the reset button is connected to the hardware reset lines, so nothing can prevent forcing the reset state.