Any hope for multiple I2S hats on Raspberry PI?

[idegani]

I had hoped to use my awesome Octo Board to capture multiple inputs, and then output to speakers using the HifiBerry Amp2:

https://www.hifiberry.com/shop/boards/hifiberry-amp2/

This should in theory be possible with ALSA. I made sure that none of the GPIO's conflict between the two hats, other than the I2S pins.

HIFIBERRY: GPIO2-3, (I2C) 4 (MUTE)

However, if I try to include both dtoverlays in my /etc/config.txt, only one registers. (whichever is last).

dtoverlay=audioinjector-addons
dtoverlay=hifiberry-dacplus

Any tips/suggestions to get these two devices working together, or should I just go with an external amp connected to an Octo output channel?

[flatmax]

Interesting idea !

Which card is going to be I2S bus master.
I would imagine it would be the Audio Injector .... but then you will have to run the other card with a 4x sample rate of the octo !

Matt