diff --git a/glasgow.nix b/glasgow.nix
new file mode 100644
index 0000000..801561c
--- /dev/null
+++ b/glasgow.nix
@@ -0,0 +1,62 @@
+{ lib
+, python3Packages
+, fetchFromGitHub
+, sdcc
+, yosys
+, icestorm
+, nextpnr
+}:
+
+with python3Packages;
+
+buildPythonApplication rec {
+  pname = "glasgow";
+  version = "unstable-2019-08-31";
+  realVersion = lib.substring 0 7 src.rev;
+
+  src = fetchFromGitHub {
+    owner = "GlasgowEmbedded";
+    repo = "Glasgow";
+    rev = "21641a13c6a0daaf8618aff3c5bfffcb26ef6cca";
+    sha256 = "1dpm1jmm4fg8xf17s6h9g5sc09gq8b6xq955sv2x11nrbqf98l4v";
+  };
+
+  nativeBuildInputs = [ sdcc ];
+
+  propagatedBuildInputs = [
+    nmigen
+    fx2
+    libusb1
+    aiohttp
+    pyvcd
+    bitarray
+    crcmod
+  ];
+
+  patches = [ ./glasgow-applet.diff ];
+  postPatch = ''
+    substituteInPlace software/setup.py \
+      --replace 'versioneer.get_version()' '"${realVersion}"'
+  '';
+
+  preBuild = ''
+    make -C firmware LIBFX2=${fx2}/share/libfx2
+    cp firmware/glasgow.ihex software/glasgow
+    cd software
+  '';
+
+  # a couple failing tests and also installCheck tries to build_ext again
+  doInstallCheck = false;
+  doCheck = false;
+
+  checkPhase = ''
+    python -m unittest discover
+  '';
+
+  meta = with lib; {
+    description = "Software for Glasgow, a digital interface multitool";
+    homepage = https://github.com/GlasgowEmbedded/Glasgow;
+    license = licenses.bsd0;
+    maintainers = with maintainers; [ emily ];
+  };
+}
diff --git a/shell.nix b/shell.nix
index 4cdec26..97b9cb0 100644
--- a/shell.nix
+++ b/shell.nix
@@ -1,58 +1,8 @@
+# This is for nixpkgs 19.09
+
 let
   pkgs = import <nixpkgs> { };
-  fx2 = pkgs.python3Packages.buildPythonPackage rec {
-    pname = "fx2";
-    version = "0.8";
-    # not using Pypi as it lacks the firmware sources
-    src = pkgs.fetchFromGitHub {
-      owner = "whitequark";
-      repo = "libfx2";
-      rev = "v${version}";
-      sha256 = "0b3zp50mschsxi2v3192dmnpw32gwblyl8aswlz9a0vx1qg3ibzn";
-    };
-    nativeBuildInputs = with pkgs; [ gnumake sdcc ];
-    propagatedBuildInputs = with pkgs.python3Packages; [ libusb1 crcmod ];
-    preBuild = ''
-      cd software
-      python setup.py build_ext
-    '';
-  };
-  nmigen = pkgs.python3Packages.buildPythonPackage rec {
-    name = "nmigen";
-    version = "0.1rc1";
-    src = pkgs.fetchgit {
-      url = "https://github.com/m-labs/nmigen";
-      rev = "v${version}";
-      sha256 = "002kyxazpc2azarfzahr17imizs0m9m5silggzx8yyy1kljxl796";
-      leaveDotGit = true;
-    };
-    checkPhase = "PATH=${pkgs.yosys}/bin:${pkgs.symbiyosys}/bin:${pkgs.yices}/bin:$PATH python -m unittest discover nmigen.test -v";
-    nativeBuildInputs = with pkgs; [ python3Packages.setuptools_scm git ];
-    propagatedBuildInputs = with pkgs.python3Packages; [ bitarray pyvcd jinja2 ];
-  };
-  glasgow = pkgs.python3Packages.buildPythonApplication rec {
-    pname = "glasgow";
-    version = "2019-10-07";
-    src = pkgs.fetchgit {
-      url = "https://github.com/GlasgowEmbedded/Glasgow";
-      rev = "bfe49bebc4483b32eed8ec127a98a9fa2e77e7d4";
-      sha256 = "0sh7l57pr49mmiqxq6g12pcln9h474gvlkfh3c439aqiv3p3jvyl";
-      fetchSubmodules = true;
-      leaveDotGit = true;
-    };
-    patches = [ ./glasgow-applet.diff ];
-    nativeBuildInputs = with pkgs; [ python3Packages.setuptools_scm git gnumake sdcc ];
-    propagatedBuildInputs = (
-      [ fx2 nmigen ] ++
-      (with pkgs.python3Packages; [ setuptools libusb1 aiohttp pyvcd bitarray crcmod ]) ++
-      (with pkgs; [ yosys nextpnr icestorm ]));
-    preBuild = ''
-      cd software
-      python setup.py build_ext
-    '';
-    # tests are currently broken since nMigen migration
-    doCheck = false;
-  };
+  glasgow = pkgs.callPackage ./glasgow.nix {};
   pyqtgraph-qt5 = pkgs.python3Packages.buildPythonPackage rec {
     name = "pyqtgraph_qt5-${version}";
     version = "0.10.0";