Thank you for the answer. Yes, I use pulseaudio and pavucontrol, which might be, as someone described "Red Hat garbage" (including the pipewire and systemd as well). The best way is to only use alsa, however setting default sound inputs, outputs, etc. is much less convenient. Also, sound in Firefox only works with pulseaudio (the workaround is to use apulse). Waterfox doesn't have this problem, so the sound works with alsa only. I will try your solution. Strange fact is that the bug is in Debian, but in my case Debian and Ubuntu keep all the sound settings perfectly after reboot. Only Devuan requires changing the sound card settings manually after every reboot. I am not the only one having this problem. I have seen many reports regarding the sound issues in Devuan on the web and in Devuan reviews on Distrowatch.