Screen is Purple and Green Lakka

Hi, I am trying to make a portable handheld console out of the Le potato.
But for some reason whenever I boot it the only colours it shows are purple/violet and green. I’ve got it to boot once with full colour, but I don’t know how I did that. It only happens like this when I plug it into (via HDMI) my 3.5 inch display. It works fine with a tv. I’m using a mobile power bank for the battery.
Here is the display I used: OSOYOO 3.5inch Touch Screen LCD Display HDMI Monitor for RPI with Stylus Pen and Protective Case Support Raspberry Pi 4 2GB / 4GB / 8GB 2 3 Model B B+ : Electronics

Thanks for helping out with this I can’t figure out what’s wrong.

What OS are you using?

Lakka. Version 4.3 it says every time I boot it.

The display is advertising it has YUV support when it really doesn’t. It only supports RGB in reality. You need to patch the EDID or try Batocera.

Batocera.linux’ So I should try this instead of lakka?

Yes, in newer Linux kernels, RGB is set as the default even if YUV is advertised. Not sure if Batocera has it but it’s newer than Lakka.

Hi again, I tried using batocera, and it isn’t compatible with my controller. (abxy don’t work)

You also mentioned ‘patching the EDID’. How do I do that?

Report the controller compatibility problem to Batocera.

For patching EDID:

  1. You have to dump the EDID.
  2. You have to get an EDID editor and disable YUV.
  3. You have to force Linux to use the EDID you provide.

Google how to do each of these steps in Linux. Also search EDID here and there’s some guides to dumping.

Recommend also asking on the Batocera forums and point them to this thread.

In the future, avoid cheap displays that advertise supporting a colorspace that it actually does not support.

I’ve got Batocera to work! I was just mapping the buttons wrong. Thank you so much for your support, it was really quick and informative.