This might not fix your problem, but it might give you some ideas to look at. A couple of those settings get rid of the black border. I checked my HDMI computer monitor, and it has a button on the side to change aspect ratios, and cycling that does the same thing. It was strange, because the Pi 3B+ worked ok on the TV's default setting. And the black lies were gone when I went back to the Pi 4. I accidentally tried 'Just scan' because I was curious. It had all the standard ones, and the default was something like 16:9. One of the reasons people with a technical background get frustrated with questions, is that they don't have crystal balls.Īnyway, I found my answer in a setting in the TV Menu that changes the Aspect Ratio of the picture. It does not say whether you are using a TV as a display or a dedicated HDMI monitor. Then I found an obscure setting to change the aspect ratio on the HDMI TV.

I had a black border around one of my screens and messed with config.txt and a heap of other stuff with no result.

Black border around screen windows 10