{ config, pkgs, lib, ... }:

{
  boot.loader.grub.enable = false;
  boot.loader.raspberryPi = {
    enable = true;
    version = 3;
    uboot.enable = true;
    uboot.configurationLimit = 1;
    firmwareConfig = ''
      gpu_mem=192
      dtparam=audio=on
      disable_overscan=1
      hdmi_drive=2
      disable_audio_dither=1

      # Can be shortened if desired.
      boot_delay=10
    '';
  };

  # This is necessary for the rpi3.
  boot.kernelPackages = pkgs.linuxPackages_rpi4;

  # Enable nonfree firmware (necessary for the rpi)
  hardware.enableRedistributableFirmware = true;

  boot.supportedFilesystems = [ "ext4" ];

  # Log important messages to the system console.
  boot.consoleLogLevel = lib.mkDefault 7;

  # These are the filesystems defined on the SD image.
  fileSystems = {
    "/boot" = {
      device = "/dev/disk/by-label/FIRMWARE";
      fsType = "vfat";
      options = [ "nofail" ];
    };
    "/" = {
      device = "/dev/disk/by-label/NIXOS_SD";
      fsType = "ext4";
    };
  };

  # Prevent use of swapspace as much as possible
  boot.kernel.sysctl = { "vm.swappiness" = 0; };

  swapDevices = [ { device = "/swap"; size = 2048; } ];
}