{ config, pkgs, lib, ... }:
{
  # NixOS wants to enable GRUB by default
  boot.loader.grub.enable = false;
  # Enables the generation of /boot/extlinux/extlinux.conf
  boot.loader.generic-extlinux-compatible.enable = true;

  # !!! Otherwise (even if you have a Raspberry Pi 2 or 3), pick this:
  boot.kernelPackages = pkgs.linuxPackages_latest;

  # A bunch of boot parameters needed for optimal runtime on RPi 3B
  boot.kernelParams = ["cma=256M"];
  boot.loader.raspberryPi.enable = true;
  boot.loader.raspberryPi.version = 3;
  boot.loader.raspberryPi.uboot.enable = true;
  boot.loader.raspberryPi.firmwareConfig = ''
    gpu_mem=256
  '';
  environment.systemPackages = with pkgs; [
    raspberrypi-tools
  ];

  # File systems configuration for using the installer's partition layout
  fileSystems = {
    "/boot" = {
      device = "/dev/disk/by-label/NIXOS_BOOT";
      fsType = "vfat";
    };
    "/" = {
      device = "/dev/disk/by-label/NIXOS_SD";
      fsType = "ext4";
    };
  };

  # !!! Adding a swap file is optional, but strongly recommended!
  swapDevices = [ { device = "/swapfile"; size = 1024; } ];

  # Configure basic SSH access
  services.openssh.enable = true;
}