I have an HDMI+USB 7" screen connected to Pi.

It gets some data from the Pi, but it displays wrong pixels. The output is not readable at all.

The screen does work with another machine. The Pi does work with another external HDMI monitor.

How can I fix my HDMI screen? What can cause such a problem?

  • What's wrong with the screen? Care to upload an image?
    – Jacobm001
    Aug 9, 2016 at 13:59
  • @Jacobm001 I just did. I did try to connect the screen usb (which powers it) to another source. I feel like these are full-height pixels. If I press CTRL + ALT + F1 to switch to tty1, it displays a black screen. Then when going back to UI, I get this white screen again. I think there should be a configuration since it's not a hardware thing. This did work before, tho, with the same setup. Aug 9, 2016 at 14:10

2 Answers 2


Since the same HDMI cable works fine with another machine and same Pi machine works fine with another monitor, my conclusion was that there is a software setting which should be fixed.

I tried to update my packages (sudo apt-get update && sudo apt-get dist-upgrade) and this did not work.

Then, I have just overridden the /boot/config.txt file. This did work. Since my screen is a 7" HDMI Display with Touchscreen, from AdaFruit, I just went to their website and overridden the config.txt file with the recommended settings.

Basically, the lines which are not commented out are:

hdmi_cvt=800 400 60 3 0 0 0

Taken from here.

Then I rebooted my Pi and it work.


Probably a bad cable. try a new HDMI cable. If not the cable than the screen might be bad.

  • Thanks, but since the same cable and display worked with another machine (a Macbook), obviously the cable was not the issue. See my answer :) Aug 14, 2016 at 12:35

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