Raspberry Pi OS - Upgrading audio for Bluetooth compatibility

On December 4th 2020, a new Raspberry Pi OS image was released featuring, among others, system-wide Bluetooth audio compatibility (Raspberry Pi Foundation Blog post). This updated image is available in the usual spots (https://www.raspberrypi.org/software/operating-systems/).

How do I update my Pi audio?

For all of us who already have a Pi configured to our personal taste, the prospect of having to reconfigure everything on a fresh image isn't joyful. Fortunately, we don't have to start with a fresh image to get the new perks of the latest update this time!

Update your Pi like you normally do (It's preferable to do it from the Pi with a screen attached this time):
```
sudo apt update
sudo apt full-upgrade
	
```
Uninstall the previous audio subsystem module blueAlsa:
```
sudo apt purge bluealsa
	
```
Delete the previous audio subsystem configuration file (this must be done in each user profile):
```
rm ~/.asoundrc
	
```
Uninstall the previous audio mixer:
```
sudo apt purge pimixer
	
```
Install the new audio subsystem module PulseAudio Bluetooth:
```
sudo apt install pulseaudio-module-bluetooth
	
```
Reboot!
```
sudo reboot now
	
```

If you use the Desktop-less "lite" image, you are done!
If you use the Desktop or the Desktop-full images, continue with the next section.

Update the Desktop controls

Now, the new audio subsystem is managing the audio, but the desktop interface still uses the old Alsa volume controls. We must exchange them:

Right-click a blank area on the taskbar, choose Add / Remove Panel Items,
Find the plugin labelled Volume Control (ALSA/BT), select it and click Remove.
Click the Add button,
Find the plugin labelled Volume Control (PulseAudio),
Click Add.

Alternatively, in the Desktop Menu, Preferences section, open the Appearance Settings application, go to the Defaults tab and press one of the Set Defaults buttons.

Source: New Raspberry Pi OS release — December 2020, 2020-12-08