Xperia 1 III: bluetooth crashes after making a call from the car's head unit

[Oversemper]

Hello! I've changed pixel 2 xl (android 11) to xperia 1 mark III and I have problems with bluetooth in my car (Mercedes-Benz GLC). When I'm making a call via the car's head unit the bluetooth app crashes on the phone and the car says "the device is not responding. Restarting the Bluetooth connection...". With pixel 2xl everything worked perfectly. When I initiate a call via the phone itself - it works ok, incoming calls - work ok, but when I try to dial a number from the car's head unit - the bluetooth app always crashes on the xperia 1 iii. I have screenshots and photos. Latest firmware: 61.0.A.11.92 Please help, thank you!

[Strampke]

First thing to do is reset Bluetooth both on car and Xperia.

In Xperia:

Settings - device connection - Bluetooth and tap the cogwheel beside the Benz and set it to forget.

Or find network connections in settings and reset.

Don't forget to restart your Xperia after doing so.

Tell the Benz to forget BT as well or reset is connections and start over again.

[Oversemper]

This was the first thing I did, delete everything, reset everything, reboot everything, even took car's battery terminal off (and it is a pain it the you know where to do it on a benz), cleared cache and system data for the bluetooth app. All in vain. Pixel 2 xl and Pixel 4a connects and benz can initiate call on them via bluetooth without any problem, but the bluetooth app on xperia 1 iii just crashes instantly.

[Strampke]

Once upon a time it helped to change AVRCP version to let's try 1.3

Curious to know if that can solve your connection problem.

[Oversemper]

I've tried every combination of AVRCP and MAP version. Each time I've cleared cache and system data of the bluetooth app and rebooted the phone and de-auth and auth the phone with the car. And most importantly, I checked again pixel 4a and it works flawlessly, it has the August's security patch (the September's one is downloaded but not installed). Xperia 1 iii currently is also on the August's security patch. Pixels 4a uses by default AVRCP 1.5 and MAP 1.2. The same settings for xperia 1 iii does not work as well as AVRCP 1.3 and all other possible combinations. Sony's support advised me to reboot xperia into Safe Mode which I did, but it does not help. Below are photos of the xperia 1 iii in safe mode (see lower left corner) failing to receive a dialing command from the car and photos of pixel 4a working flawlessly.

[Oversemper]

Here is a video of me trying to call 112 via car's head united connected to the xperia 1 mark iii:

video deleted

[Oversemper · Accepted solution]

This bug has been fixed for me by the new firmware - 61.0.A.14.3. Without any de-auth/re-auth, just works now! Thanks to everybody!