Raspberry Pi and config.txt

Hello there.

I followed nix.dev to install NixOS on a Raspberry Pi.

Now I need to add something to config.txt. The guide says:

  • To tweak bootloader options affecting hardware, see config.txt options and change the options by running mount /dev/disk/by-label/FIRMWARE /mnt and opening /mnt/config.txt .

I added dtoverlay=gpio-ir,gpio_pin=23 to get my IR receiver to work, but when I try ir-keytable it says No devices found. How can I check if the config.txt is applied?

Here is the output of

dtc -I fs /sys/firmware/devicetree/base

The output is the same after I remove dtoverlay=gpio-ir,gpio_pin=23 from config.txt, leading me to believe that it does not work…

I used one of these overlays https://github.com/raspberrypi/linux/tree/326dea65f88e75d25960ecce49df23a0d76bbac0/arch/arm/boot/dts/overlays

With the ovmerge Perl script: https://github.com/raspberrypi/utils/blob/53f7816f275c1b77b6cc8d51e4efa7e863a7c40e/ovmerge/ovmerge

It spit out an overlay that I tried to apply with hardware.deviceTree.overlays, with no success…

May be related:

Yay! Replacing the compatible line works.

1 Like

Can you elaborate on how you got the gpio-ir-overlay working?

I want to to run lirc and tried adding the overlay via hardware.deviceTree.overlays, but have trouble following along.