I have a GT1 beelink (S912, 2MB RAM) and Coreelec 8.90.4.
Automatic refresh rate switching does not work for me.
In Libreelec and FTMC (on android) there are no problems with that.
Stay tuned for 8.90.5
for me it works with no problem.
Have you added the resolution/framerate combination to your resolution whitelist?
You’re right. I did not know that the white list is empty by default. Thank you for your help.