anchor.diff:        "https://bitcoincore.org/bin/bitcoin-core-${version}/bitcoin-${version}.tar.gz"
         "https://bitcoin.org/bin/bitcoin-core-${version}/bitcoin-${version}.tar.gz"
       ];
  -    sha256 = "4bbd62fd6acfa5e9864ebf37a24a04bc2dcfe3e3222f056056288d854c53b978";
  +    sha256 = "1a91202c62ee49fb64d57a52b8d6d01cd392fffcbef257b573800f9289655f37";
     };
   
     nativeBuildInputs =
  
positive.code: 
  with stdenv.lib;
  let
    version = "0.20.1";
    majorMinorVersion = versions.majorMinor version;
    desktop = fetchurl {
      url = "https://raw.githubusercontent.com/bitcoin-core/packaging/${majorMinorVersion}/debian/bitcoin-qt.desktop";
  
negative.code:     ++ optional withGui wrapQtAppsHook;
    buildInputs = [ boost zlib zeromq miniupnpc libevent ]
      ++ optionals stdenv.isLinux [ util-linux ]
      ++ optionals withWallet [ db48 sqlite ]
      ++ optionals withGui [ qtbase qttools qrencode ];
  
    postInstall = optional withGui ''
  