Setup and configs all look good. We try to load the dtoverlay immediately, that fails, but it is known that this does not always work (sadly), so we allow it to fail. On boot it shows that -517 error, not sure if that is expected or not. Sadly there are quite a few expected kernel errors during RPi boot, like the vcsm/vhci one that is known to show up but is expected when GPU memory is below 32M.
Little search: https://audiophilestyle.com/forums/topic/54677-dmesg-errors-for-allo-boss-should-i-be-concerned/
Ah lol one on our forum: https://dietpi.com/forum/t/dmesg-warning-snd-allo-boss-dac-soc-snd-soc-register-card/2673/1
So this seems to be expected indeed and the final “mapping ok” shows that all went well. I don’t like such kind of errors, probably we can report this to the RPi firmware repository: https://github.com/raspberrypi/firmware/issues
Maybe loading the driver later would already prevent those errors.
You say there is no sound when you enable the equaliser. The “-eq” suffix is correct and the way the script detects whether to enable it or not, but that is removed before applying it to config.txt as you can see in the console output. But when you disable the equaliser, does it it work?
In general it could make sense to play a bid with the alsamixer settings: alsamixer
Would not be the first time that some control is set to “mute” by default.
Which RPi model btw?
Just found the tech details PDF from Allo: https://www.allo.com/sparky/boss-dac.html#downloads (“Preferred Setup Values”)
It contains as well which ALSA mixer controls are available and their default values. Probably that helps.