rk3326-r35s-linux.dtb is the file with the working FN Button
You'd have to edit the boot.ini file on your boot folder or use my provided boot.ini file.
[!NOTE]
Newer R33S/R35S/R36S consoles are coming with 4 new updated screens. If your brand new R33S/R35S/R36S doesn't work with the usual DTB files look at the new screens folder and try which one works for you.