output

error: The option value `environment.systemPackages.[definition 2-entry 1]' in `.../sd-image.nix' is not of type `package'.

sd-image.nix

# Cribbed from https://nixos.wiki/wiki/NixOS_on_ARM#Build_your_own_image                                                                                                                                           
# On an Aarch64-capable system, build with:                                                                                                                                                                        
# $ nix-build '<nixpkgs/nixos>' -A config.system.build.sdImage -I nixos-config=./sd-image.nix                                                                                                                      
{ pkgs, unzip, mock, ... }: {
  imports = [
    <nixpkgs/nixos/modules/installer/cd-dvd/sd-image-aarch64.nix>
  ];
  environment.systemPackages = [
    pkgs.tahoe-lafs.overrideAttrs (old: {
      buildInputs = [ unzip mock ];
    })
  ];
}