Description
What happened?
With my RockPi-S I go to armbian-config overlay selection and I enable s0-ext-antenna however this shows up while booting:
Applying kernel provided DT overlay rk3308-s0-ext-antenna.dtbo
failed on fdt_overlay_apply(): FDT_ERR_NOTFOUND
226 bytes read in 6 ms (36.1 KiB/s)
Doing git archeology this happens because the dts for s0-ext-antenna target symbols like board_antenna that are defined in board-rocks0-0001-deviceTree.patch but not in rk3308-rock-pi-s.dts (file in upstream linux).
However looking at the hardware the wifi setup for the rock-pi-s0 and rock-pi look different:
On the Rock-Pi-S0, we can clearly spot an RF Switch IC (tiny black SMD component at the center of the following screenshot), with impedance matched traces going to the Ceramic antenna, the ufl connector and the SOM:
However on the Rock-Pi-S there is no such switch, or built-in ceramic antenna to begin with, we can spot the Realtek WiFi+BT IC, a π matching network and impedance matched traces straight to the antenna connector:
Critically I do not see an RF Switch IC or a builtin ceramic antenna.
So if my understanding is correct rk3308-s0-ext-antenna.dtbo should not be compiled to begin with given there is no built-in antenna to begin with on the Rock Pi S.