I just renamed the file to .dtbo and it works again. Reason below:
"UPDATE: The Dynamic Device Tree support in the kernel requires a different format of "local fixups" in the overlay. To avoid problems with old and new styles of overlay coexisting, and to match other users of overlays, the old "name-overlay.dtb" naming scheme has been replaced with "name.dtbo" from 4.4 onwards. Overlays should be referred to by name alone, and the firmware or utility that loads them will append the appropriate suffix."
I just renamed the file to .dtbo and it works again. Reason below:
"UPDATE: The Dynamic Device Tree support in the kernel requires a different format of "local fixups" in the overlay. To avoid problems with old and new styles of overlay coexisting, and to match other users of overlays, the old "name-overlay.dtb" naming scheme has been replaced with "name.dtbo" from 4.4 onwards. Overlays should be referred to by name alone, and the firmware or utility that loads them will append the appropriate suffix."
source: https://www.raspberrypi.org/documentation/configuration/config-txt.md