anchor.diff:  
     meta = with stdenv.lib; {
       description = "facetimehd firmware";
  -    homepage = https://support.apple.com/downloads/DL1849;
  +    homepage = https://support.apple.com/downloads/DL1877;
       license = licenses.unfree;
       maintainers = [ maintainers.womfoo ];
       platforms = platforms.linux;
  
positive.code: stdenv.mkDerivation {
  
    name = "facetimehd-firmware-${version}";
  
    src = fetchurl {
      url = "https://support.apple.com/downloads/DL1849/en_US/osxupd10.11.2.dmg";
      sha256 = "1jw6sy9vj27amfak83cs2c7q856y4mk1wix3rl4q10yvd9bl4k9x";
      curlOpts = "-r ${dmgRange}";
    };
  
  
negative.code: 
  let
  
    version = "1.43_4";
  
  
    # Updated according to https://github.com/patjak/bcwc_pcie/pull/81/files
    # and https://github.com/patjak/bcwc_pcie/blob/5a7083bd98b38ef3bd223f7ee531d58f4fb0fe7c/firmware/Makefile#L3-L9
    # and https://github.com/patjak/bcwc_pcie/blob/5a7083bd98b38ef3bd223f7ee531d58f4fb0fe7c/firmware/extract-firmware.sh
  
    # From the Makefile:
    dmgUrl = "https://support.apple.com/downloads/DL1877/en_US/osxupd10.11.5.dmg";
    dmgRange = "205261917-208085450"; # the whole download is 1.3GB, this cuts it down to 2MB
    # Notes:
    # 1. Be sure to update the sha256 below in the fetch_url
    # 2. Be sure to update the homepage in the meta
  
    # Also from the Makefile (OS_DRV, OS_DRV_DIR), but seems to not change:
    firmwareIn = "./System/Library/Extensions/AppleCameraInterface.kext/Contents/MacOS/AppleCameraInterface";
    firmwareOut = "firmware.bin";
  
    # The following are from the extract-firmware.sh
    firmwareOffset = "81920"; # Variable: firmw_offsets
    firmwareSize = "603715"; # Variable: firmw_sizes
  
  
    # separated this here as the script will fail without the 'exit 0'
    unpack = pkgs.writeScriptBin "unpack" ''
  