HDMI on Raspberry PI not working unless monitor connected before booting
The HDMI output of the Raspberry Pi is only activated if a monitor or television is connected and powered up before the Raspberry Pi is turned on.
To correct this –
- edit the /boot/config.txt file
- Add the following two lines
hdmi_force_hotplug=1
hdmi_drive=2 - save the changes
From now on – even if you dont plug in the HDMI cable when you turn on your pi, the hdmi will be working!