Two weeks ago I put LibreELEC on an MXQ Pro 4K using the LibreELEC-S905.arm-8.0-8.0.1h image, downloaded gxbb_p200_1G_100M.dtb, renamed that to dtb.img an added it to SD card. I booted the box without any single problem and my remote control worked. Today I tried a second MXQ Pro 4k, same supplier but I think a different version since the remote has small differences. I tried installing LibreELEC the same way with a fresh install on a new SD card (32 instead of 16). It boots, but my remote is not working. I connected mouse and keyboard to do the setup and connecting wireless als gave me an error: Network error. Did not receive a reply. Possible causes include: remote app. After that initial error it connected, but my remote is still not working and also a USB keyboard that worked during the installation no longer works. Are these problems related to the device tree? I don’t really care about the keyboard, but getting the remote working is very important for me.
EDIT: can I try replacing the dtb on the SD card with another one? Or do I have to do a fresh start and burn the LibreELEC image on the SD card again?
Maybe try to load without any dtb at all, because it could be taken from internal memory of your device.
You definitely can try other device trees (dtb) files. Actually one with Realtek WiFi may work. Try different files.
If all parts of the box's hardware work it means you're on right device tree.