I have a Raspberry Pi Zero and I am using the Adafruit I2S MEMS Microphone together with the ADAFRUIT I2S 3W CLASS D AMPLIFIER BREAKOUT - MAX98357A.

I did follow the two respective tutorials and I got both the mic and the speaker working. However, I do need to disable the microphone or the amp + speaker won't work.

There seems to be a conflict regarding the I2S bus.

According to this forum post it can be done.

pi zero


I have the following /etc/modules:


The /boot/config.txt looks like so:

# ... 
# ... 

This is what I see in dmesg when I have both the mic and the amplifier enabled:

[ 13.039895] asoc-simple-card asoc-simple-card.0: snd-soc-dummy-dai <-> 20203000.i2s mapping ok
[ 13.660674] bcm2835-i2s 20203000.i2s: Trying to bind component to card "snd_rpi_hifiberry_dac" but is already bound to card "snd_rpi_simple_card"
[ 13.660700] snd-hifiberry-dac soc:sound: ASoC: failed to instantiate card -19
[13.661278] snd-hifiberry-dac soc:sound: snd_soc_register_card() failed: -19

Contradictings instructions

The two adafruit tutorials for the mic and the amp are conflicting. The mic tutorial tells me to enable the snd-bcm2835 module:

Add snd-bcm2835 on its own line, to the modules file as shown below

While the amp tutorial tells me to disable the module:

However, if you see the following line:


Put a # in front of it

Please note the different typing using both a dash and an underscore snd_bcm2835 vs. snd-bcm2835.


1 Answer 1


I was also getting the same error. But now it is working for me. First you install I2S microphone as shown here: https://learn.adafruit.com/adafruit-i2s-mems-microphone-breakout/raspberry-pi-wiring-and-test

After that while you are installing I2S amplifier go to the detailed installation section and skip the first 2 steps and start from "Create asound.conf file" and at last reboot your pi.

Update: Please note that using the aplay.service which constantly sends audio to the audio output will break the microphone.

Not the answer you're looking for? Browse other questions tagged or ask your own question.