anchor.diff:        cd src
         git config user.email "build-daemon@nixos.org"
         git config user.name "Nixos Build Daemon $name"
  -      git remote add base git://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git
  -      git remote add iwl git://git.kernel.org/pub/scm/linux/kernel/git/iwlwifi/linux-firmware.git
  -      git fetch base $baseRev
  -      git checkout -b work FETCH_HEAD
  -      git fetch iwl $iwlRev
  -      git merge FETCH_HEAD)
  +      git remote add base https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git
  +      git remote add iwl https://git.kernel.org/pub/scm/linux/kernel/git/iwlwifi/linux-firmware.git
  +      git fetch --shallow-since=$shallowSince base
  +      git fetch --shallow-since=$shallowSince iwl
  +      git checkout -b work $baseRev
  +      git merge $iwlRev)
       rm -rf src/.git
       cp -a src $out
     '';
  
positive.code:   # update version to the more recent commit date
  
    src = runCommand "firmware-linux-nonfree-src-merged-${version}" {
      # When updating this, you need to let it run with a wrong hash, in order to find out the desired hash
      baseRev = "bf04291309d3169c0ad3b8db52564235bbd08e30";
      iwlRev = "iwlwifi-fw-2017-11-03";
  
      # randomly mutate the hash to break out of fixed hash, when updating
      outputHash = "11izv1vpq9ixlqdss19lzs5q289d7jxr5kgf6iymk4alxznffd8z";
  
      outputHashAlgo = "sha256";
      outputHashMode = "recursive";
      buildInputs = [ git gnupg ];
      NIX_SSL_CERT_FILE = "${cacert}/etc/ssl/certs/ca-bundle.crt";
    } ''
  
negative.code: 
  stdenv.mkDerivation rec {
    name = "firmware-linux-nonfree-${version}";
    version = "2017-10-13-${src.iwlRev}";
  
    # The src runCommand automates the process of building a merged repository of both
    #
    # https://git.kernel.org/cgit/linux/kernel/git/firmware/linux-firmware.git/
    # https://git.kernel.org/cgit/linux/kernel/git/iwlwifi/linux-firmware.git/
    #
    # This gives us up to date iwlwifi firmware as well as
    # the usual set of firmware. firmware/linux-firmware usually lags kernel releases
  