If you've had issues getting your Raspberry Pi 4 to work with specific HDMI displays (monitors, TV's etc.) this tutorial has got you covered! It's a quick fix that just requires a bit of tinkering in the config.txt file that's present on all Raspberry Pi's. We've had a quite a few members of our community phone in with this specific issue, so we will try to do our best to remedy the problem for every situation!
Everything that we’re doing will be done by editing the config.txt file. You can do this by viewing the contents of your micro SD card on a computer and opening the config.txt file from the boot directory in a text editor. Our preferred method though is just by editing it directly in the terminal on your Pi. It’s easier and much cleaner. To do this, open a new terminal window and enter the following:
sudo nano /boot/config.txt
Modifying config.txt
All of the coming lines to be modified in config.txt may or may not already be in the file. When going through these, make sure you only add 1 copy of each of these lines (check they aren't there already), or if they are commented out (# symbol in Python) you simply just uncomment them, not add them in.
The lines you need to add are:
hdmi_force_hotplug=1
hdmi_drive=2
hdmi_safe=1
core_freq_min=500
Once you've done this hit CTRL+X then Y then Enter and you will return to the Pi's Terminal. Reboot the Pi and it should solve the issues! If you have done it directly through the boot files on the microSD card, simply eject the microSD card and put it back into the Pi and power it on.
