Thanks elbuit and also djspawn, for your efforts.
I managed to install the LibreELEC-Generic_S905.arm-9.2.8.13 on my Nexbox MXQ PRO with Amlogic S905 SoC. PCB board is the same as elbuit's (but for some reason remote did not work neither with his neither with djspawn's firmware). Anyway I used djspawn's modded firmware as starting point since the LED-s are working as supposed with it. I should note that starting with "toothpick (AV) reboot switch" was not working for me, but terminal emulator for android did. I just executed "reboot update" and booted right to dtech's LibreELEC build. Also USB flash drive was not booting, but SD card worked.
Installed to internal emmc storarage. Wifi was fine from the first boot (box has Realtek 8189etv) but Ethernet was not working until I used gxbb_p201.dtb as dtb.img.
So just a short list for what I did:
- flashed djspawn's modded firmware with Amlogic USB Burning Tool v2.0.7.2, via malemale USB cable
- booted to Android OS and istalled jackpal.androidterm-1.0.70-71-minAPI4.apk (search for android terminal apk)
- executed "reboot update" and booted right to LibreELEC
Maybe somebody finds this helpfull, as I did other ppl's posts... Cheers.