On my Orange Pi 5, I have successfully installed the X11VNC server. I followed the guide at the following link X11VNC and everything works as expected. I can connect with Real VNC from another device and see the desktop of the Orange Pi as if I were in front of its display. However, when the Orange Pi 5 is powered on without a display connected to the HDMI port, the access with Real VNC doesn't work as before. I get a black screen and I am unable to interact with the Orange Pi. I had a similar issue with Raspberry Pi, where I could resolve it by setting a default screen resolution. How can I achieve this with Armbian? How can I configure an alternative resolution when the HDMI port is not connected?