{
  description = "Firmware for Sinara Fast-Servo based on Not-OS and Linien";
  
  inputs.nixpkgs.url = github:NixOS/nixpkgs/nixos-unstable;
  inputs.not-os.url = github:cleverca22/not-os;
  inputs.not-os.inputs.nixpkgs.follows = "nixpkgs";
  
  outputs = { self, nixpkgs, not-os }:
    let
      pkgs = import nixpkgs { system = "x86_64-linux"; };

      gnu-platform = "arm-none-eabi";

      binutils-pkg = { zlib, extraConfigureFlags ? [] }: pkgs.stdenv.mkDerivation rec {
        basename = "binutils";
        version = "2.30";
        name = "${basename}-${gnu-platform}-${version}";
        src = pkgs.fetchurl {
          url = "https://ftp.gnu.org/gnu/binutils/binutils-${version}.tar.bz2";
          sha256 = "028cklfqaab24glva1ks2aqa1zxa6w6xmc8q34zs1sb7h22dxspg";
        };
        configureFlags = [
          "--enable-deterministic-archives"
          "--target=${gnu-platform}"
          "--with-cpu=cortex-a9"
          "--with-fpu=vfpv3"
          "--with-float=hard"
          "--with-mode=thumb"
        ] ++ extraConfigureFlags;
        outputs = [ "out" "info" "man" ];
        depsBuildBuild = [ pkgs.buildPackages.stdenv.cc ];
        buildInputs = [ zlib ];
        enableParallelBuilding = true;
        meta = {
          description = "Tools for manipulating binaries (linker, assembler, etc.)";
          longDescription = ''
            The GNU Binutils are a collection of binary tools.  The main
            ones are `ld' (the GNU linker) and `as' (the GNU assembler).
            They also include the BFD (Binary File Descriptor) library,
            `gprof', `nm', `strip', etc.
          '';
          homepage = http://www.gnu.org/software/binutils/;
          license = pkgs.lib.licenses.gpl3Plus;
          /* Give binutils a lower priority than gcc-wrapper to prevent a
            collision due to the ld/as wrappers/symlinks in the latter. */
          priority = "10";
        };
      };

      gcc-pkg = { gmp, mpfr, libmpc, platform-binutils, extraConfigureFlags ? [] }: pkgs.stdenv.mkDerivation rec {
        basename = "gcc";
        version = "9.1.0";
        name = "${basename}-${gnu-platform}-${version}";
        src = pkgs.fetchurl {
          url = "https://ftp.gnu.org/gnu/gcc/gcc-${version}/gcc-${version}.tar.xz";
          sha256 = "1817nc2bqdc251k0lpc51cimna7v68xjrnvqzvc50q3ax4s6i9kr";
        };
        preConfigure = ''
          mkdir build
          cd build
        '';
        configureScript = "../configure";
        configureFlags = [ 
          "--target=${gnu-platform}"
          "--with-arch=armv7-a"
          "--with-tune=cortex-a9"
          "--with-fpu=vfpv3"
          "--with-float=hard"
          "--disable-libssp"
          "--enable-languages=c"
          "--with-as=${platform-binutils}/bin/${gnu-platform}-as"
          "--with-ld=${platform-binutils}/bin/${gnu-platform}-ld" ] ++ extraConfigureFlags;
        outputs = [ "out" "info" "man" ];
        hardeningDisable = [ "format" "pie" ];
        propagatedBuildInputs = [ gmp mpfr libmpc platform-binutils ];
        enableParallelBuilding = true;
        dontFixup = true;
      };

      newlib-pkg = { platform-binutils, platform-gcc }: pkgs.stdenv.mkDerivation rec {
        pname = "newlib";
        version = "3.1.0";
        src = pkgs.fetchurl {
          url = "ftp://sourceware.org/pub/newlib/newlib-${version}.tar.gz";
          sha256 = "0ahh3n079zjp7d9wynggwrnrs27440aac04340chf1p9476a2kzv";
        };
        nativeBuildInputs = [ platform-binutils platform-gcc ];
        configureFlags = [
          "--target=${gnu-platform}"

          "--with-cpu=cortex-a9"
          "--with-fpu=vfpv3"
          "--with-float=hard"
          "--with-mode=thumb"
          "--enable-interwork"
          "--disable-multilib"

          "--disable-newlib-supplied-syscalls"
          "--with-gnu-ld"
          "--with-gnu-as"
          "--disable-newlib-io-float"
          "--disable-werror"
        ];
        dontFixup = true;
      };
      
      gnutoolchain = rec {
        binutils-bootstrap = pkgs.callPackage binutils-pkg { };
        gcc-bootstrap = pkgs.callPackage gcc-pkg {
          platform-binutils = binutils-bootstrap;
          extraConfigureFlags = [ "--disable-libgcc" ];
        };
        newlib = pkgs.callPackage newlib-pkg {
          platform-binutils = binutils-bootstrap;
          platform-gcc = gcc-bootstrap;
        };
        binutils = pkgs.callPackage binutils-pkg {
          extraConfigureFlags = [ "--with-lib-path=${newlib}/arm-none-eabi/lib" ];
        };
        gcc = pkgs.callPackage gcc-pkg {
          platform-binutils = binutils;
          extraConfigureFlags = [ "--enable-newlib" "--with-headers=${newlib}/arm-none-eabi/include" ];
        };
      };

      mkbootimage = pkgs.stdenv.mkDerivation {
        pname = "mkbootimage";
        version = "2.3dev";

        src = pkgs.fetchFromGitHub {
          owner = "antmicro";
          repo = "zynq-mkbootimage";
          rev = "872363ce32c249f8278cf107bc6d3bdeb38d849f";
          sha256 = "sha256-5FPyAhUWZDwHbqmp9J2ZXTmjaXPz+dzrJMolaNwADHs=";
        };

        propagatedBuildInputs = [ pkgs.libelf pkgs.pcre ];
        patchPhase = ''
          substituteInPlace Makefile --replace "git rev-parse --short HEAD" "echo nix"
        '';
        installPhase = ''
          mkdir -p $out/bin
          cp mkbootimage $out/bin
        '';
        # fix crash; see https://github.com/xmrig/xmrig/issues/3305
        hardeningDisable = [ "fortify" ];
      };

      fsbl = { board ? "zc706" }: pkgs.stdenv.mkDerivation {
        name = "${board}-fsbl";
        src = pkgs.fetchFromGitHub {
          owner = "Xilinx";
          repo = "embeddedsw";
          rev = "65c849ed46c88c67457e1fc742744f96db968ff1";
          sha256 = "1rvl06ha40dzd6s9aa4sylmksh4xb9dqaxq462lffv1fdk342pda";
        };
        patches = [ ./fsbl.patch ];
        nativeBuildInputs = [
          pkgs.gnumake
          gnutoolchain.binutils
          gnutoolchain.gcc
        ];
        patchPhase = ''
          patch -p1 -i ${./fsbl.patch}
          patchShebangs lib/sw_apps/zynq_fsbl/misc/copy_bsp.sh
          echo 'SEARCH_DIR("${gnutoolchain.newlib}/arm-none-eabi/lib");' >> lib/sw_apps/zynq_fsbl/src/lscript.ld
        '';
        buildPhase = ''
          cd lib/sw_apps/zynq_fsbl/src
          make BOARD=${board} "CFLAGS=-DFSBL_DEBUG_INFO -g"
        '';
        installPhase = ''
          mkdir $out
          cp fsbl.elf $out
        '';
        doCheck = false;
        dontFixup = true;
      };

      u-boot = { board ? "zc706" }: pkgs.pkgsCross.armv7l-hf-multiplatform.buildUBoot {
        defconfig = "xilinx_zynq_virt_defconfig";
        preConfigure = ''
          export DEVICE_TREE=zynq-${board}
        '';
        extraMeta.platforms = ["armv7l-linux"];
        filesToInstall = ["u-boot.elf"];
      };

      bootimage = { board ? "zc706" }: pkgs.runCommand "${board}-bootimage"
        {
          buildInputs = [ mkbootimage ];
        }
        ''
          bifdir=`mktemp -d`
          cd $bifdir
          ln -s ${fsbl { inherit board; }}/fsbl.elf fsbl.elf
          ln -s ${u-boot { inherit board; }}/u-boot.elf u-boot.elf
          cat > boot.bif << EOF
          the_ROM_image:
          {
            [bootloader]fsbl.elf
            u-boot.elf
          }
          EOF
          mkdir $out $out/nix-support
          mkbootimage boot.bif $out/boot.bin
          echo file binary-dist $out/boot.bin >> $out/nix-support/hydra-build-products
        '';
      
      not-os-configured = (import "${not-os}" {
          inherit nixpkgs;
          extraModules = [
            "${not-os}/zynq_image.nix"
          ];
          platform = system: (import nixpkgs { config = {}; }).platforms.armv7l-hf-multiplatform;
          system = "x86_64-linux";
          crossSystem.system = "armv7l-linux";
        });
    in {
      packages.x86_64-linux = {
        inherit mkbootimage;
      };
      packages.armv7l-linux = {
        zc706-u-boot = u-boot { board = "zc706"; };
        zc706-fsbl = fsbl { board = "zc706"; };
        zc706-bootimage = bootimage { board = "zc706"; };
        zc706-not-os = not-os-configured.config.system.build.zynq_image;
      };
    };
}