On postmarketOS edge and v25.06 (not released yet, images/own builds before 2025-06-17), the main speaker is currently not working for the OnePlus 6 and 6T.
If you are affected by this:
1) Stop and disable the alsa-restore systemd service:
# systemctl disable --now alsa-restore
2) Ensure systemctl status alsa-restore now says the service is stopped and disabled.
# systemctl status alsa-restore
3) Remove /var/lib/alsa/asound.state
# rm /var/lib/alsa/asound.state
4) Reboot
When using openrc instead of systemd, adapt the instructions accordingly to stop and disable the alsa openrc service.
So far we only saw reports of the OP6 and OP6T being affected by this. If you ran into this bug with another device, have related problems and need help, or want to help us get to the bottom of this and make a more proper fix than this workaround then let us know in the related issue #3747 or in chat.
EDIT 2025-06-20: instructions have been updated after related MR has been merged.
EDIT 2025-06-22: instructions adjusted so it works with other devices too