diff --git a/shell.nix b/shell.nix
index 1014333..83954a3 100644
--- a/shell.nix
+++ b/shell.nix
@@ -1,41 +1,14 @@
 let
-  yosys_overlay = self: super:
-    rec {
-      yosys = super.yosys.overrideAttrs(oa: rec {
-        name = "yosys-${version}";
-        version = "0.9";
-        srcs = [
-          (super.fetchFromGitHub {
-            owner  = "yosyshq";
-            repo   = "yosys";
-            rev    = "yosys-${version}";
-            sha256 = "0lb9r055h8y1vj2z8gm4ip0v06j5mk7f9zx9gi67kkqb7g4rhjli";
-            name   = "yosys";
-          })
-          # NOTE: the version of abc used here is synchronized with
-          # the one in the yosys Makefile of the version above;
-          # keep them the same for quality purposes.
-          (super.fetchFromGitHub {
-            owner  = "berkeley-abc";
-            repo   = "abc";
-            rev    = "3709744c60696c5e3f4cc123939921ce8107fe04";
-            sha256 = "18a9cjng3qfalq8m9az5ck1y5h4l2pf9ycrvkzs9hn82b1j7vrax";
-            name   = "yosys-abc";
-          })
-        ];
-        buildInputs = oa.buildInputs ++ [ super.zlib ];
-      });
-    };
-  pkgs = import <nixpkgs> { overlays = [ yosys_overlay ]; };
+  pkgs = import <nixpkgs> { };
   fx2 = pkgs.python3Packages.buildPythonPackage rec {
     pname = "fx2";
-    version = "0.7";
+    version = "0.8";
     # not using Pypi as it lacks the firmware sources
     src = pkgs.fetchFromGitHub {
       owner = "whitequark";
       repo = "libfx2";
       rev = "v${version}";
-      sha256 = "0xvlmx6ym0ylrvnlqzf18d475wa0mfci7wkdbv30gl3hgdhsppjz";
+      sha256 = "0b3zp50mschsxi2v3192dmnpw32gwblyl8aswlz9a0vx1qg3ibzn";
     };
     nativeBuildInputs = with pkgs; [ gnumake sdcc ];
     propagatedBuildInputs = with pkgs.python3Packages; [ libusb1 crcmod ];
@@ -46,31 +19,32 @@ let
   };
   nmigen = pkgs.python3Packages.buildPythonPackage {
     name = "nmigen";
-    version = "2019-08-26";
-    src = pkgs.fetchFromGitHub {
-      owner = "m-labs";
-      repo = "nmigen";
-      rev = "2168ff512bfe04806b35c09d3b1d265a16c4ddbc";
-      sha256 = "0ij9idvlqsjzzr50vyg2ziabj7lv7yi8s0826g3acrn45hfv4535";
+    version = "2019-10-06";
+    src = pkgs.fetchgit {
+      url = "https://github.com/m-labs/nmigen";
+      rev = "2512a9a12d2c062b8f34330c379ec523b125f38d";
+      sha256 = "0mi2snd8daabdmcbmc10hxzjmnmx85rnx1njqmrj1ll2jin3ncq7";
+      leaveDotGit = true;
     };
     checkPhase = "PATH=${pkgs.yosys}/bin:${pkgs.symbiyosys}/bin:${pkgs.yices}/bin:$PATH python -m unittest discover nmigen.test -v";
+    nativeBuildInputs = with pkgs; [ pkgs.python3Packages.setuptools_scm git ];
     propagatedBuildInputs = with pkgs.python3Packages; [ bitarray pyvcd jinja2 ];
   };
   glasgow = pkgs.python3Packages.buildPythonApplication rec {
     pname = "glasgow";
-    version = "2019-08-28";
-    src = pkgs.fetchFromGitHub {
-      owner = "GlasgowEmbedded";
-      repo = "Glasgow";
-      rev = "c103a8fc7945a0e46fb8b50fab63c51efe27e242";
-      sha256 = "0mfzjf74w71yasbj9jvdx86ipc3wrmxiqa819b586k9dsskzgw32";
+    version = "2019-10-07";
+    src = pkgs.fetchgit {
+      url = "https://github.com/GlasgowEmbedded/Glasgow";
+      rev = "bfe49bebc4483b32eed8ec127a98a9fa2e77e7d4";
+      sha256 = "0wvn7ysixgxm35ghdp0cdqfp5pxpbxvr1r9d5amcz3ss6bd2844c";
       fetchSubmodules = true;
+      leaveDotGit = true;
     };
     patches = [ ./glasgow-applet.diff ];
-    nativeBuildInputs = with pkgs; [ gnumake sdcc ];
+    nativeBuildInputs = with pkgs; [ pkgs.python3Packages.setuptools_scm git gnumake sdcc ];
     propagatedBuildInputs = (
       [ fx2 nmigen ] ++
-      (with pkgs.python3Packages; [ libusb1 aiohttp pyvcd bitarray crcmod ]) ++
+      (with pkgs.python3Packages; [ setuptools libusb1 aiohttp pyvcd bitarray crcmod ]) ++
       (with pkgs; [ yosys nextpnr icestorm ]));
     preBuild = ''
       cd software