nixfiles/hosts/raspberry/services/btattach.nix

{ pkgs, ... }: {
  systemd.services.btattach = {
    before = [ "bluetooth.service" ];
    after = [ "dev-ttyAMA0.device" ];
    wantedBy = [ "multi-user.target" ];
    serviceConfig = {
      ExecStart = "${pkgs.bluez}/bin/btattach -B /dev/ttyS1 -P bcm -S 3000000";
    };
  };
}