I have had a boot video on retropie/emulation station for a while, but the sound wouldn’t work! I couldn’t figure out why, but then I looked into it and realized that HDMI takes audio. I am running HDMI and AUX, assuming AUX SHOULD take over, which it does during roms and etc, but it does not during the boot sequence.
Took me a while of digging and looking up online, I finally fixed it haha.
So this is what I did
sudo nano /boot/config.txt
added line “hdmi_ignore_edid_audio=1”
CTRL-X — Y
This basically “Pretends all audio formats are unsupported by display. This means ALSA will default to analogue.”
TL:DR: If your AUX isn’t working on your boot video when you use HDMI for display, you need to add this line of config.