$ sudo modprobe snd-i2s_rpi rpi_platform_generation=0
# rpi_platform_generation=0 for Raspberry Pi 1 B/A/A+, 0
# do not add anything for everything else (2/3).
In order for arecord to detect the mic on bootup for Raspberry Pi 1 (as I had) and Zero, creating /etc/modprobe.d/snd-i2s_rpi.conf with the following line:
options snd-i2s_rpi rpi_platform_generation=0
should allow the module to load with that option by default.
Testing with sudo modprobe snd-i2s_rpi after generating that config should also work.
To quote from the README:
In order for
arecordto detect the mic on bootup for Raspberry Pi 1 (as I had) and Zero, creating/etc/modprobe.d/snd-i2s_rpi.confwith the following line:should allow the module to load with that option by default.
Testing with
sudo modprobe snd-i2s_rpiafter generating that config should also work.