Giles replied to the topic 'How Update Kstars on Astroberry RPi4' in the forum. 3 years ago

The way the HDMI works on the Pi is that if it is already booted up and you then connect a monitor then you just see a blank screen.
I have found it necessary to have the screen connected and powered up, and then turn on the Pi - you should see something on the screen even before it finds the boot image.

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