How to activate HDMI as my default output starting from BIOS, GRUB, GDM, and Desktop?

Solution 1:

Usually this is selectable in the BIOS of the machine. I have a system with an NVidia card that has both HDMI and VGA outputs. In the BIOS, I had to select "Primary Display Port" as "HDMI", and then it would always default to HDMI for BIOS, grub, console, etc output.