Sorry for the typo. I use gxl_p212_1g.dtb (I've edited my previous post).
It works for me.
The box is the same, but I know that there are different models with the same external box and reference.
I'm using LibreELEC-S905.arm-8.2-8.2.3.1.img.gz with gxl_p212_1g.dtb renamed as dtb.img on the sdcard.
Sorry that it doesn't work for you...