@Lolonois Yes, I see it with "amixer". I never used this command. I will remember to check that everytime.

Now i'm working on the fully broken system :

I removed pulseaudio and pipewire. Now I can select vc4-hdmi-0 or vc4-hdmi-1 in Retropie audio menu and in raspi-config menu.

here is the amixer output :

Simple mixer control 'PCM',0 Capabilities: pvolume Playback channels: Front Left - Front Right Limits: Playback 0 - 255 Mono: Front Left: Playback 255 [100%] [0.00dB] Front Right: Playback 255 [100%] [0.00dB] Simple mixer control 'HDMI',0 Capabilities: pvolume pswitch Playback channels: Front Left - Front Right Limits: Playback 0 - 255 Mono: Front Left: Playback 255 [100%] [0.00dB] [on] Front Right: Playback 255 [100%] [0.00dB] [on]

Sound still not working, with hdmi-0 or hdmi-1 and PCM or HDMI in ES menu. sliders working but no sound. This time "MASTER" is stuck at 0%. I understand why now.

When I go in audio Retropie-setup Menu I can see an error during one second :

lvl0: Audio manager error: unable to open SDL audio : Alsa Couldn't open audio device: Device or ressource busy.

After there is the two hdmi choices and the working "Mixer - adjust output volume" Option.
I try to "Reset to default", reboot, nothing changes.

In raspi-config, 6-Advanced Options, A7-Audio Config, there is "No audio systems installed".

vc4-hdmi-0 and vc4-hdmi-1 are still availlable in 1-System Options, S2 Audio.

I updated SDL1 and SDL2 dependency packages in RetroPie Setup. Nothing changes.

yet another no audio (but through 3.5 jack this time)