4A is contacting the Bluetooth-Manager API in the boot phase and for unknown reason, the BT hw controller and bluez are not initialized correctly at that time. As a consequence, no bluetooth controller is detected by 4A BT plugin and BT audio are then disabled without any consequence on the rest of the audio stack.
This only happens at boot time: as soon as things are initialized, a simple restart of 4A service is enough to enable BT audio and stream music through A2DP.
|16837,8||4A: delay service startup as a workaround to SPEC-1762/SPEC-1763 (temp workaround)||master||AGL/meta-agl-devel||Status: MERGED||+2||+1|
|16855,2||4A: delay service startup as a workaround to SPEC-1762/SPEC-1763 (temp workaround)||flounder||AGL/meta-agl-devel||Status: MERGED||+2||+1|
|20307,2||binding: bluetooth: add adapter_changes event||master||apps/agl-service-bluetooth||Status: MERGED||+2||+1|
|20910,1||binding: bluetooth: add adapter_changes event||guppy||apps/agl-service-bluetooth||Status: MERGED||+2||+1|