iwlwifi-firmware-blacklist.nix

{
  # iwlwifi firmware v22 has severe problems with 4.9 kernels. Blacklist the
  # -22 firmware version; 21 is known good.
  #
  # The mkForce is _necessary_, because otherwise the default values for
  # hardware.firmware ([kernel]) would be merged in, and the -22 would come
  # from them as well.
  hardware.firmware = lib.mkForce [
    (lib.overrideDerivation pkgs.firmwareLinuxNonfree (drv: {
      postInstall = ''
        rm $out/lib/firmware/iwlwifi-8000C-22.ucode
      '';
    }))
  ];
}