{ config, lib, pkgs, modulesPath, platform, ... }: {
  # Build this image with:
  # nix build .#nixosConfigurations.nixos-rpi4-img.config.system.build.sdImage
  nixpkgs.hostPlatform.system = "aarch64-linux";
  nixpkgs.buildPlatform.system = "x86_64-linux";
  nixpkgs.crossSystem.system = "armv7l-linux";
  networking.hostName = "nixos-rpi4-img";
  networking.firewall.allowedTCPPorts = [ 22 ];
}