diff --git a/nixpkgs b/nixpkgs
index 8d536f3..d00b5a5 160000
--- a/nixpkgs
+++ b/nixpkgs
@@ -1 +1 @@
-Subproject commit 8d536f36256d30d8fa47b24caafb1af6405889f3
+Subproject commit d00b5a5fa6fe8bdf7005abb06c46ae0245aec8b5
diff --git a/nixpkgs.nix b/nixpkgs.nix
index ac48a41..18eb9c9 100644
--- a/nixpkgs.nix
+++ b/nixpkgs.nix
@@ -25,4 +25,4 @@ if builtins.getEnv "STATIC_HASKELL_NIX_CI_NIXPKGS_UNSTABLE_BUILD" == "1"
     if builtins.pathExists ./nixpkgs/pkgs
       then import ./nixpkgs {}
       # Pinned nixpkgs version; should be kept up-to-date with our submodule.
-      else import (fetchTarball https://github.com/nh2/nixpkgs/archive/8d536f36256d30d8fa47b24caafb1af6405889f3.tar.gz) {}
+      else import (fetchTarball https://github.com/NixOS/nixpkgs/archive/d00b5a5fa6fe8bdf7005abb06c46ae0245aec8b5.tar.gz) {}
diff --git a/static-stack2nix-builder-example/default.nix b/static-stack2nix-builder-example/default.nix
index e3490f7..3529fe8 100644
--- a/static-stack2nix-builder-example/default.nix
+++ b/static-stack2nix-builder-example/default.nix
@@ -13,7 +13,7 @@ let
     if builtins.pathExists ../.in-static-haskell-nix
       then toString ../. # for the case that we're in static-haskell-nix itself, so that CI always builds the latest version.
       # Update this hash to use a different `static-haskell-nix` version:
-      else fetchTarball https://github.com/nh2/static-haskell-nix/archive/39f2f38ed042e84d8b6627a236c1815f48023d3c.tar.gz;
+      else fetchTarball https://github.com/nh2/static-haskell-nix/archive/57147ba740363712f589d24dfa005c8c7f6d1056.tar.gz;
 
   # Pin nixpkgs version
   # By default to the one `static-haskell-nix` provides, but you may also give
diff --git a/survey/default.nix b/survey/default.nix
index abd40b9..46d8066 100644
--- a/survey/default.nix
+++ b/survey/default.nix
@@ -1,16 +1,4 @@
 let
-  cython-disable-tests-overlay = final: previous: {
-    python27 = previous.python27.override {
-      packageOverrides = self: super: {
-        cython = super.cython.overridePythonAttrs (old: rec {
-          # TODO Remove once Cython tests are no longer flaky. See
-          #   https://github.com/nh2/static-haskell-nix/issues/6#issuecomment-420452838
-          #   https://github.com/cython/cython/issues/2602
-          doCheck = false;
-        });
-      };
-    };
-  };
 in
 
 {
@@ -31,7 +19,6 @@ in
   # Note that we must NOT use something like `import normalPkgs.path {}`.
   # It is bad because it removes previous overlays.
   pkgs ? (normalPkgs.appendOverlays [
-    cython-disable-tests-overlay
   ])."${approach}",
 
   # When changing this, also change the default version of Cabal declared below
@@ -126,7 +113,7 @@ let
   stackagePackages =
     let
       stackageInfoPath = pkgs.path + "/pkgs/development/haskell-modules/configuration-hackage2nix/stackage.yaml";
-      pythonWithYaml = pkgs.python2Packages.python.withPackages (pkgs: [pkgs.pyyaml]);
+      pythonWithYaml = normalPkgs.python3Packages.python.withPackages (pkgs: [pkgs.pyyaml]);
       stackage-packages-file = normalPkgs.runCommand "stackage-packages" {} ''
         ${pythonWithYaml}/bin/python -c 'import yaml, json; x = yaml.load(open("${stackageInfoPath}")); print(json.dumps([line.split(" ")[0] for line in x["default-package-overrides"]]))' > $out
       '';
@@ -1126,7 +1113,7 @@ let
               # Test suite tries to connect to dbus, can't work in sandbox.
               credential-store = dontCheck super.credential-store;
 
-              # Test suite calls all kinds of shell unilities, can't work in sandbox.
+              # Test suite calls all kinds of shell utilities, can't work in sandbox.
               dotenv = dontCheck super.dotenv;
 
               # Test suite fails time-dependently:
@@ -1343,6 +1330,9 @@ let
                   ])
                   "--libs nettle sdl2 SDL2_image xcursor libpng libjpeg libtiff-4 libwebp";
 
+              # Test hangs for 10 hours on CI machine.
+              midi = dontCheck super.midi;
+
               # With optimisations disabled, some tests of its test suite don't
               # finish within the 25 seconds timeout.
               skylighting-core =