DAC hat not detected with Pi 3 (64-bit) OS

New user here.
I have an Inno-Maker DAC HAT (hardware is definitely supported).
For some reason when I deploy using the Pi 3 64-bit OS, I can’t get audio from the DAC HAT, just the onboard headphone jack.
The DAC outputs work just fine on a Pi 4 64-bit OS (and hardware).
The DAC works just fine on the same Pi 3b on a Pi 3 32-bit install.

I’m using the exact same custom configuration for BALENA_HOST_CONFIG_dtoverlay
(the second string is because I’m using a BT dongle because of the Pi3 bluetooth/wifi conflict. I’ve tried removing that string but no fix).

I create the fleet from scratch every time, so I don’t think that’s the issue.

When I manually changed the Device Variable AUDIO_OUTPUT to DAC (From Auto) I got an error message in the log:
WARNING: No DAC found. Falling back to PulseAudio defaults.

This is a standalone device, so I’m happy enough using the 32-bit version, but it could be nice to explore multi-room audio with newer Pi models on 64-bit architecture. Any help appreciated as to what might be causing the 64-bit pi 3 OS to reject the DAC.

Sidenote - I found this issue with some 64-bit balenasound versions:

But the suggested fix of removing the “vc4-kms-v3d” overlay from the device configuration didn’t fix it.


Can you please confirm which version of balenaOS you are using for Raspberry Pi 3 (64bit)?