diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 0a8e97f..22107d3 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -18,14 +18,14 @@ jobs:
       - uses: actions/checkout@v4
         with:
           submodules: true
-          fetch-depth: 0
+          fetch-depth: 1
       - name: Install Nix
-        uses: cachix/install-nix-action@V28
+        uses: cachix/install-nix-action@v30
         with:
           nix_path: nixpkgs=channel:nixos-unstable
       - name: Build
-        run: nix --experimental-features 'nix-command flakes' build -L "git+file://$(pwd)?submodules=1&rev=$(git rev-parse HEAD)"
+        run: nix --experimental-features 'nix-command flakes' build -L '.?submodules=1#'
       - name: Flake check
-        run: nix --experimental-features 'nix-command flakes' flake check "git+file://$(pwd)?submodules=1&rev=$(git rev-parse HEAD)"
+        run: nix --experimental-features 'nix-command flakes' flake check '.?submodules=1#'
       - name: Format
         run: nix --experimental-features 'nix-command flakes' fmt && git diff --exit-code
diff --git a/flake.lock b/flake.lock
index 4079e55..3f74b9d 100644
--- a/flake.lock
+++ b/flake.lock
@@ -5,11 +5,11 @@
         "systems": "systems"
       },
       "locked": {
-        "lastModified": 1710146030,
-        "narHash": "sha256-SZ5L6eA7HJ/nmkzGG7/ISclqe6oZdOZTNoesiInkXPQ=",
+        "lastModified": 1731533236,
+        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
         "owner": "numtide",
         "repo": "flake-utils",
-        "rev": "b1d9ab70662946ef0850d488da1c9019f3a9752a",
+        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
         "type": "github"
       },
       "original": {
@@ -19,11 +19,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1724395761,
-        "narHash": "sha256-zRkDV/nbrnp3Y8oCADf5ETl1sDrdmAW6/bBVJ8EbIdQ=",
+        "lastModified": 1737942377,
+        "narHash": "sha256-8Eo/jRAgT3CbAloyqOj6uPN1EqBvLI/Tv2g+RxHjkhU=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "ae815cee91b417be55d43781eb4b73ae1ecc396c",
+        "rev": "88a55dffa4d44d294c74c298daf75824dc0aafb5",
         "type": "github"
       },
       "original": {
diff --git a/flake.nix b/flake.nix
index ea7eaa9..b221ed5 100644
--- a/flake.nix
+++ b/flake.nix
@@ -7,7 +7,7 @@
     nixpkgs,
   }: let
     inherit (flake-utils.lib) eachDefaultSystem;
-    inherit (nixpkgs.lib) hasSuffix composeManyExtensions;
+    inherit (nixpkgs.lib) assertMsg;
     rev = self.shortRev or self.dirtyShortRev or "unknown";
 
     shvspy = {
@@ -19,49 +19,41 @@
       copyDesktopItems,
       makeDesktopItem,
     }:
-      stdenv.mkDerivation {
-        name = "shvspy-${rev}";
-        src = builtins.path {
-          path = ./.;
-          filter = path: _: ! hasSuffix ".nix" path;
+      assert assertMsg self.submodules
+      "Unable to build without submodules. Append '?submodules=1#' to the URL.";
+        stdenv.mkDerivation {
+          name = "shvspy-${rev}";
+          src = ./.;
+          buildInputs = [
+            qt6.wrapQtAppsHook
+            qt6.qtbase
+            qt6.qtserialport
+            qt6.qtwebsockets
+            qt6.qtsvg
+            qt6.qtnetworkauth
+            doctest
+            openldap
+          ];
+          nativeBuildInputs = [
+            cmake
+            qt6.qttools
+            copyDesktopItems
+          ];
+          desktopItems = [
+            (makeDesktopItem {
+              name = "shvspy";
+              exec = "shvspy";
+              desktopName = "SHVSpy";
+              categories = ["Network" "RemoteAccess"];
+            })
+          ];
+          cmakeFlags = ["-DUSE_QT6=ON"];
+          meta.mainProgram = "shvspy";
         };
-        buildInputs = [
-          qt6.wrapQtAppsHook
-          qt6.qtbase
-          qt6.qtserialport
-          qt6.qtwebsockets
-          qt6.qtsvg
-          qt6.qtnetworkauth
-          doctest
-          openldap
-        ];
-        nativeBuildInputs = [
-          cmake
-          qt6.qttools
-          copyDesktopItems
-        ];
-        desktopItems = [
-          (makeDesktopItem {
-            name = "shvspy";
-            exec = "shvspy";
-            desktopName = "SHVSpy";
-            categories = ["Network" "RemoteAccess"];
-          })
-        ];
-        cmakeFlags = [
-          "-DUSE_QT6=ON"
-        ];
-        meta.mainProgram = "shvspy";
-      };
   in
     {
-      overlays = {
-        pkgs = final: _: {
-          shvspy = final.callPackage shvspy {};
-        };
-        default = composeManyExtensions [
-          self.overlays.pkgs
-        ];
+      overlays.default = final: _: {
+        shvspy = final.callPackage shvspy {};
       };
     }
     // eachDefaultSystem (system: let