I’m using hdmi for the first time with the GPD Pocket 1. I noticed when I plugged in the micro hdmi cable and turned on the system, it is defaulting to the behaviour of using the external display as the primary display – the GPD display is off. Even when in “off but charging” mode, the battery indicator shows on the external display.
In linux, it detects both screens but only content is displayed on the hdmi screen. If I touch the screen, I can see the touch panel. Linux thinks the display is on, and will send content to it.
In the BIOS, in the LCD section, there is a boot display option, which was set to “auto” but even when I change it to eDP (the gpd’s display), the behaviour is the same.