While working on LineageOS for the FP3 I fell over this. It’s based on the device config from Motorola G7 which has a working radio. The radio device is also provided by the kernel. So I played little bit around and got the error codes from the FM-Radio app solved. However the signal level seems not to be enough. I tried with several headphones. This is part of the logcat output I get:
04-23 00:25:46.392 3124 3288 D FMRadio : Received event. Count: 1
04-23 00:25:46.392 3124 3288 D FMRadio : Received <2>
04-23 00:25:46.392 3124 3288 D FMRadio : Got SEEK_COMPLETE_EVENT
04-23 00:25:46.392 3124 3288 E android_hardware_fm: index: 1
04-23 00:25:46.470 3124 3288 E android_hardware_fm: Free the buffer
04-23 00:25:46.470 3124 3288 D FMRadio : Received event. Count: 4
04-23 00:25:46.471 3124 3288 D FMRadio : Received <1>
04-23 00:25:46.471 3124 3288 D FMRadio : Got TUNE_EVENT
04-23 00:25:46.471 3124 3288 D android_hardware_fm: BT soc is
04-23 00:25:46.471 3124 3288 V FMRadio : Current state is 0
04-23 00:25:46.471 3124 3288 V FMRadio : RxEvtList: CURRENT-STATE : Search ---> NEW-STATE : FMRxOn
04-23 00:25:46.471 3124 3288 D FMService: FmRxEvSearchComplete: Tuned Frequency: 103000
04-23 00:25:46.471 3124 3288 D FmSharedPreferences: Save preferences
04-23 00:25:46.472 3124 3288 D FMRadio : mServiceCallbacks.onSearchComplete :
04-23 00:25:46.472 3124 3288 D FMService: startNotification
04-23 00:25:46.472 3124 3124 D FMRadio : mSearchComplete:
04-23 00:25:46.482 3124 3288 D FMRadio : Received <8>
04-23 00:25:46.482 3124 3288 D FMRadio : Got BELOW_TH_EVENT
04-23 00:25:46.482 3124 3288 D FMService: FmRxEvServiceAvailable
04-23 00:25:46.482 3124 3288 D FMService: FmRxEvServiceAvailable: Tuned frequency is below signal threshold level
04-23 00:25:46.483 3124 3288 D FMRadio : Received <11>
04-23 00:25:46.483 3124 3288 D FMRadio : Got MONO_EVENT
04-23 00:25:46.483 3124 3288 D FMService: FmRxEvStereoStatus: false
04-23 00:25:46.483 3124 3288 D FMRadio : mServiceCallbacks.onAudioUpdate :2
04-23 00:25:46.483 3124 3288 D FMRadio : Received <13>
04-23 00:25:46.483 3124 3288 D FMRadio : Got RDS_NOT_AVAL_EVENT
04-23 00:25:46.483 3124 3288 D FMService: FmRxEvRdsLockStatus: false
04-23 00:25:46.483 3124 3288 D FMRadio : mServiceCallbacks.onStationRDSSupported :false
So I guess some hardware wiring or antenna components are missing. Maybe someone with hardware knowledge can check for that on the PCB.
To me personally it wouldn’t matter too much if FP3 would lack FM capabilities. I never use it. However it would be a pity for you guys who miss it.