[4.0.1.48] No sound in BT headset after upgrade to Koli

REPRODUCIBILITY (% or how often): 100%
BUILD ID = OS VERSION (Settings > About product): Sailfish OS 4.0.1.48 (Koli)
HARDWARE (XA2, Xperia 10…): Jolla C
UI LANGUAGE: Russian
REGRESSION: (compared to previous public release: Yes, No, ?): Yes

DESCRIPTION:

After the upgrade to SFOS 4.0.1.48 (Koli) my phone (Jolla C) lost the ability to play sound via Sennheiser PCX550 bt headset. The headset itself is almost new and works well. It has been paired with the phone and connects reliably. I can hear its service voice messages like “Heaset is On”, “Phone 1 is connected”, etc.

HOWEVER, all sound that should be played from the phone is mute. The phone’s speaker is silent too. The volume at both the phone and the PXC550 is set to maximum. This same headset was tested and worked perfectly with the same phone under SFOS 3.

The Settings/Bluetooth page says (back translation):

Device Name: PCX 550
Type: Headset
Supported profiles: HSP, A2DP, AVRCP, HFP, DID, GATT
Low power services: BAS 

I have mpris-proxy installed.

PRECONDITIONS:

SFOS 4.0 Koli, Sennheiser PXC 550

STEPS TO REPRODUCE:

  1. Turn on bluetooth, wait until the headset connects to the SFOS phone.
  2. Try to play any music or IP radio.

EXPECTED RESULT:

Music is heard from the headphones.

ACTUAL RESULT:

Nothing can be heard.

ADDITIONAL INFORMATION:

Another (sound-wise lower class) BT headset “JBL Everest Elite 150NC” works and plays audio even after the upgrade to SFOS 4. Here is its device info.

Device Name: JBL Everest Elite 150NC
Type: Headset
Supported profiles: SPP, A2DP, AVRCP, HFP, DID

Links to info about both headsets:


https://jbl.com/EVEREST+ELITE+150NC.html
The PXC550 still works AND PLAYS audio with a Jolla1 running SFOS 3.4.0.24 .

This regression remained in Kvarken as well. Please, fix!