diff --git a/flake.nix b/flake.nix
index 7fba407..8721ba1 100644
--- a/flake.nix
+++ b/flake.nix
@@ -7,6 +7,9 @@
       inherit (nixpkgs) lib;
 
       mypkgs = pkgs:
+        {
+          iso = import lib/gen-iso.nix lib pkgs.system;
+        } //
         (lib.mapAttrs'
           (name: type: {
             name = lib.removeSuffix ".nix" name;
@@ -46,7 +49,6 @@
     in
     {
       lib = {
-        gen-iso = import lib/gen-iso.nix lib;
         gen-ssh-config = import lib/gen-ssh-config.nix lib;
         ssh-keys = import lib/ssh-keys.nix;
       };
diff --git a/lib/gen-iso.nix b/lib/gen-iso.nix
index 197994a..7b67d06 100644
--- a/lib/gen-iso.nix
+++ b/lib/gen-iso.nix
@@ -1,17 +1,17 @@
 lib:
-
-{ system, modules ? [ ] }:
+system:
 
 let
-  cd-minimal = { modulesPath, ... }: {
-    imports = [
-      "${modulesPath}/installer/cd-dvd/installation-cd-minimal.nix"
-    ];
-  };
-
   sys = lib.nixosSystem {
     inherit system;
-    modules = [ cd-minimal ] ++ modules;
+    modules = [
+      ({ modulesPath, ... }: {
+        imports = [
+          "${modulesPath}/installer/cd-dvd/installation-cd-minimal.nix"
+        ];
+        isoImage.squashfsCompression = "gzip -Xcompression-level 1";
+      })
+    ];
   };
 
 in