anchor.diff:        dtc
         flex
         openssl
  -      (buildPackages.python2.withPackages (p: [ p.libfdt ]))
  +      (buildPackages.python3.withPackages (p: [ p.libfdt ]))
         swig
       ];
       depsBuildBuild = [ buildPackages.stdenv.cc ];
  
positive.code: 
      src = if src == null then defaultSrc else src;
  
      patches = [
        # Submitted upstream: https://patchwork.ozlabs.org/patch/1203693/
        (fetchpatch {
          url = https://github.com/dezgeg/u-boot/commit/extlinux-path-length-2018-03.patch;
          sha256 = "07jafdnxvqv8lz256qy29agjc2k1zj5ad4k28r1w5qkhwj4ixmf8";
        })
        # Submitted upstream: https://patchwork.ozlabs.org/patch/1203678/
        (fetchpatch {
          name = "rockchip-allow-loading-larger-kernels.patch";
          url = "https://marc.info/?l=u-boot&m=157537843004298&q=raw";
          sha256 = "0l3l88cc9xkxkraql82pfgpx6nqn4dj7cvfaagh5pzfwkxyw0n3p";
        })
      ] ++ extraPatches;
  
      postPatch = ''
        patchShebangs tools
  
negative.code: }:
  
  let
    defaultVersion = "2020.01";
    defaultSrc = fetchurl {
      url = "ftp://ftp.denx.de/pub/u-boot/u-boot-${defaultVersion}.tar.bz2";
      sha256 = "1w9ml4jl15q6ixpdqzspxjnl7d3rgxd7f99ms1xv5c8869h3qida";
    };
    buildUBoot = {
      version ? null
  