diff --git a/default.nix b/default.nix
index 4263960ff..2e6fd36c5 100644
--- a/default.nix
+++ b/default.nix
@@ -10,17 +10,30 @@ let
   nixpkgs =
     args.nixpkgs or (pinnedNixpkgs { inherit localSystem crossSystem; });
 
-  inherit (nixpkgs) stdenv buildPackages fetchgit llvmPackages;
+  inherit (nixpkgs) stdenv buildPackages llvmPackages;
 
-  src = self.outPath or ./.;
+  src = self.outPath or (builtins.fetchGit ./.);
   version = self.lastModified or "unstable";
 
   inherit (stdenv) lib targetPlatform;
   specs = with targetPlatform;
-    [ ] ++ lib.optional is32bit "32bit" ++ lib.optional is64bit "64bit"
-    ++ lib.optional isAarch32 "arm" ++ lib.optional isAarch64 "arm_64"
-    ++ lib.optional isRiscV "riscv" ++ lib.optional isx86 "x86"
-    ++ lib.optional isx86_32 "x86_32" ++ lib.optional isx86_64 "x86_64";
+    [ ]
+
+    ++ lib.optional is32bit "32bit"
+
+    ++ lib.optional is64bit "64bit"
+
+    ++ lib.optional isAarch32 "arm"
+
+    ++ lib.optional isAarch64 "arm_64"
+
+    ++ lib.optional isRiscV "riscv"
+
+    ++ lib.optional isx86 "x86"
+
+    ++ lib.optional isx86_32 "x86_32"
+
+    ++ lib.optional isx86_64 "x86_64";
 
   buildRepo = { repo, repoInputs }:
     let
@@ -85,7 +98,6 @@ let
         for R in repos/*; do
           [ "$R" != "repos/$repo" ] && find $R -name Tupfile -delete
         done
-        find repos/gems -name Tupfile -delete
 
         # Scan repository and generate script
         tup init
diff --git a/flake.nix b/flake.nix
index c04960f0c..fca5efe38 100644
--- a/flake.nix
+++ b/flake.nix
@@ -5,16 +5,53 @@
 
   inputs.nixpkgs.uri = "git+https://gitea.c3d2.de/ehmry/nixpkgs.git?ref=genode";
 
-  outputs = { self, nixpkgs }: {
-    packages = nixpkgs.lib.forAllCrossSystems
-      ({ system, localSystem, crossSystem }:
-        import ./default.nix {
+  outputs = { self, nixpkgs }:
+    let
+      mkOutput = { system, localSystem, crossSystem }: rec {
+        packages = import ./default.nix {
           inherit localSystem crossSystem self;
           nixpkgs = builtins.getAttr system nixpkgs.legacyPackages;
-        });
+        };
+        defaultPackage = packages.base-linux;
+      };
 
-    defaultPackage.x86_64-linux = self.packages.x86_64-linux-x86_64-genode.os;
+      localSystems = [ "x86_64-linux" ];
+      crossSystems = [ "x86_64-genode" ];
+
+      forAllCrossSystems = f:
+        with builtins;
+        let
+          f' = localSystem: crossSystem:
+            let system = localSystem + "-" + crossSystem;
+            in {
+              name = system;
+              value = f { inherit system localSystem crossSystem; };
+            };
+          list = nixpkgs.lib.lists.crossLists f' [ localSystems crossSystems ];
+          attrSet = listToAttrs list;
+        in attrSet;
+
+      finalize = outputs:
+        with builtins;
+        let
+          outputs' = outputs // {
+            x86_64-linux = getAttr "x86_64-linux-x86_64-genode" outputs;
+          };
+          systems = attrNames outputs';
+          outputAttrs = attrNames (head (attrValues outputs'));
+
+          list = map (attr: {
+            name = attr;
+            value = listToAttrs (map (system: {
+              name = system;
+              value = getAttr attr (getAttr system outputs');
+            }) systems);
+          }) outputAttrs;
+
+        in listToAttrs list;
+
+      final = finalize (forAllCrossSystems mkOutput);
+
+    in final;
 
-    hydraJobs = self.packages;
-  };
 }