diff --git a/checks/default.nix b/checks/default.nix
index 66d5b0b..526f8d1 100644
--- a/checks/default.nix
+++ b/checks/default.nix
@@ -4,23 +4,17 @@
   pkgs,
   deployPkgs,
   ...
-}:
+}@inputs:
 {
   ${system} = {
 
-    # Check project formatting
-    format = pkgs.runCommand "nixfmt-check" { } ''
-      set -euo pipefail
-      cd ${self}
-      ${self.formatter.${system}}/bin/formatter . --check
-      mkdir $out
-    '';
+    # TODO: Check project formatting
 
     nixos-modules = pkgs.callPackage ./nixos-modules {
       inherit (self.lib) getSubDirs isFolderWithFile;
     };
 
-    #TODO(#29): Integration/System tests
+    nixos-configurations = import ./nixos-configurations inputs;
 
     # Import deploy-rs tests
   } // (deployPkgs.deploy-rs.lib.deployChecks self.deploy);
diff --git a/checks/nixos-configurations/default.nix b/checks/nixos-configurations/default.nix
new file mode 100644
index 0000000..e05772d
--- /dev/null
+++ b/checks/nixos-configurations/default.nix
@@ -0,0 +1,4 @@
+{ self, pkgs, ... }:
+pkgs.linkFarmFromDrvs "all" (
+  pkgs.lib.mapAttrsToList (n: v: v.config.system.build.toplevel) self.nixosConfigurations
+)
diff --git a/checks/packages/default.nix b/checks/packages/default.nix
new file mode 100644
index 0000000..dbd8049
--- /dev/null
+++ b/checks/packages/default.nix
@@ -0,0 +1,5 @@
+{ self, pkgs, ... }:
+let
+  inherit (pkgs.lib) attrValues;
+in
+pkgs.linkFarmFromDrvs "all" (attrValues self.packages)
diff --git a/deploy/docs-ops/default.nix b/deploy/docs-ops/default.nix
index 01c25d1..7fcf9ae 100644
--- a/deploy/docs-ops/default.nix
+++ b/deploy/docs-ops/default.nix
@@ -1,6 +1,5 @@
 {
   deployPkgs,
-  pkgs,
   self,
   system,
   ...
diff --git a/flake.lock b/flake.lock
index 18386cf..efd9243 100644
--- a/flake.lock
+++ b/flake.lock
@@ -111,10 +111,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1737552783,
-        "narHash": "sha256-pJ2lp36L3++a5HtdN7ULcVpdB4j7yo90TDayWuAO+T8=",
-        "rev": "33cf80043c64ddd6882268430454e3cbe98b692b",
-        "revCount": 11,
+        "lastModified": 1742849713,
+        "narHash": "sha256-EH3vvMdalGxxvYt3tZI4K4RKT/YAh7XejYYrf/jZ0N8=",
+        "ref": "refs/heads/main",
+        "rev": "f79080b8802eec4463bb4a25c64f82f73e6e31db",
+        "revCount": 12,
         "type": "git",
         "url": "file:./private"
       },
diff --git a/flake.nix b/flake.nix
index d9dae25..5c19098 100644
--- a/flake.nix
+++ b/flake.nix
@@ -23,7 +23,12 @@
   };
 
   outputs =
-    { nixpkgs-nixos-unstable, deploy-rs, ... }@inputs:
+    {
+      self,
+      nixpkgs-nixos-unstable,
+      deploy-rs,
+      ...
+    }@inputs:
     let
       system = "x86_64-linux";
       # Packages for development and build process
@@ -40,22 +45,79 @@
           })
         ];
       };
-      importParams = inputs // {
-        inherit pkgs;
-        inherit deployPkgs;
-        inherit system;
+      importParams = {
+        inherit (inputs)
+          deploy-rs
+          disko
+          nixpkgs-nixos-stable
+          sops-nix
+          private
+          ;
+        inherit pkgs deployPkgs system;
+        flakeSelf = self;
       };
     in
     {
-      checks = import ./checks/default.nix importParams;
-      deploy = import ./deploy/default.nix importParams;
-      devShells = import ./dev-shells/default.nix importParams;
-      formatter.${system} = pkgs.writeShellScriptBin "formatter" ''
-        ${pkgs.findutils}/bin/find $1 -type f -name '*.nix' -exec ${pkgs.nixfmt-rfc-style}/bin/nixfmt ''${@:2} {} +
-      '';
-      nixosConfigurations = import ./nixos-configurations/default.nix importParams;
-      nixosModules = import ./nixos-modules/default.nix importParams;
-      packages = import ./packages/default.nix importParams;
-      lib = import ./lib/default.nix importParams;
+      checks = import ./checks/default.nix (
+        importParams
+        // {
+          self = {
+            inherit (self)
+              lib
+              packages
+              nixosModules
+              nixosConfigurations
+              deploy
+              ;
+          };
+        }
+      );
+      deploy = import ./deploy/default.nix (
+        importParams
+        // {
+          self = {
+            inherit (self)
+              lib
+              packages
+              nixosModules
+              nixosConfigurations
+              ;
+          };
+        }
+      );
+      devShells = import ./dev-shells/default.nix (
+        importParams
+        // {
+          self = {
+            inherit (self) lib packages;
+          };
+        }
+      );
+      formatter.${system} = pkgs.nixfmt-tree;
+      nixosConfigurations = import ./nixos-configurations/default.nix (
+        importParams
+        // {
+          self = {
+            inherit (self) lib packages nixosModules;
+          };
+        }
+      );
+      nixosModules = import ./nixos-modules/default.nix (
+        importParams
+        // {
+          self = {
+            inherit (self) lib packages;
+          };
+        }
+      );
+      packages = import ./packages/default.nix (
+        importParams
+        // {
+          self = {
+            inherit (self) lib packages;
+          };
+        }
+      );
+      lib = import ./lib/default.nix { inherit pkgs; };
     };
 }
diff --git a/nixos-configurations/default.nix b/nixos-configurations/default.nix
index 00253e0..2aac144 100644
--- a/nixos-configurations/default.nix
+++ b/nixos-configurations/default.nix
@@ -7,27 +7,23 @@
   ...
 }@inputs:
 let
+  inherit (pkgs.lib) genAttrs;
+  inherit (nixpkgs-nixos-stable.lib) nixosSystem;
   configs = self.lib.foldersWithNix ./.;
 in
-pkgs.lib.genAttrs configs (
+genAttrs configs (
   config:
-  nixpkgs-nixos-stable.lib.nixosSystem {
+  nixosSystem {
     system = "x86_64-linux";
     specialArgs = {
       inherit inputs;
     };
     modules = [
-      self.nixosModules.default
-      ./${config}/default.nix
       disko.nixosModules.disko
       sops-nix.nixosModules.sops
-      (
-        { ... }:
-        {
-          system.extraSystemBuilderCmds = "ln -s ${self} $out/nixos-configuration";
-          imports = [ ./secrets.nix ];
-        }
-      )
+      self.nixosModules.default
+      ./${config}/default.nix
+      ./secrets.nix
     ];
   }
 )
diff --git a/nixos-configurations/lindberg-build/applications/nixpkgs-cache.nix b/nixos-configurations/lindberg-build/applications/nixpkgs-cache.nix
index f097544..66807ed 100644
--- a/nixos-configurations/lindberg-build/applications/nixpkgs-cache.nix
+++ b/nixos-configurations/lindberg-build/applications/nixpkgs-cache.nix
@@ -1,8 +1,7 @@
-{ config, pkgs, ... }:
+{ config, ... }:
 {
   qois.nixpkgs-cache = {
     enable = true;
-    hostname = "nixpkgs-cache.qo.is";
     dnsResolvers = [ config.qois.meta.network.virtual.lindberg-vms-nat.hosts.lindberg.v4.ip ];
   };
 }
diff --git a/nixos-modules/default.nix b/nixos-modules/default.nix
index 0afd3b1..7c852dc 100644
--- a/nixos-modules/default.nix
+++ b/nixos-modules/default.nix
@@ -1,8 +1,9 @@
-inputs: {
+{ private, self, ... }:
+{
   default =
-    { config, pkgs, ... }:
+    { ... }:
     {
 
-      imports = (inputs.self.lib.loadSubmodulesFrom ./.) ++ [ inputs.private.nixosModules.default ];
+      imports = (self.lib.loadSubmodulesFrom ./.) ++ [ private.nixosModules.default ];
     };
 }
diff --git a/nixos-modules/nixpkgs-cache/default.nix b/nixos-modules/nixpkgs-cache/default.nix
index 12c55ef..aaea877 100644
--- a/nixos-modules/nixpkgs-cache/default.nix
+++ b/nixos-modules/nixpkgs-cache/default.nix
@@ -16,6 +16,7 @@ with lib;
     hostname = mkOption {
       type = types.str;
       example = "mycache.myhost.org";
+      default = "nixpkgs-cache.qo.is";
       description = "Hostname, under which the cache is served";
     };
 
diff --git a/nixos-modules/system/default.nix b/nixos-modules/system/default.nix
index ed0dfb5..6742c53 100644
--- a/nixos-modules/system/default.nix
+++ b/nixos-modules/system/default.nix
@@ -57,7 +57,7 @@
     settings =
       let
         substituters = [
-          "https://${inputs.self.nixosConfigurations.lindberg-build.config.qois.nixpkgs-cache.hostname}?priority=39"
+          "https://${config.qois.nixpkgs-cache.hostname}?priority=39"
           "https://cache.nixos.org?priority=40"
           "https://attic.qo.is/qois-infrastructure"
         ];
diff --git a/nixos-modules/system/overlays.nix b/nixos-modules/system/overlays.nix
index f89be8f..ead7458 100644
--- a/nixos-modules/system/overlays.nix
+++ b/nixos-modules/system/overlays.nix
@@ -7,6 +7,5 @@
 }:
 
 {
-  nixpkgs.overlays = [ (import ../../overlays) ];
   nix.nixPath = options.nix.nixPath.default;
 }
diff --git a/overlays/default.nix b/overlays/default.nix
deleted file mode 100644
index 430b766..0000000
--- a/overlays/default.nix
+++ /dev/null
@@ -1,5 +0,0 @@
-self: super: {
-  lib = (super.lib or { }) // {
-    qois = import ../lib { lib = self.lib; };
-  };
-}
diff --git a/packages/default.nix b/packages/default.nix
index c4dc1bf..1e991b9 100644
--- a/packages/default.nix
+++ b/packages/default.nix
@@ -1,37 +1,28 @@
 {
   self,
+  flakeSelf,
   system,
+  private,
   pkgs,
   ...
 }:
-with pkgs.lib;
+let
+  inherit (self.lib) foldersWithNix;
+  inherit (pkgs.lib)
+    path
+    genAttrs
+    ;
+in
 {
-  ${system} =
-    let
-      packages = pipe (self.lib.foldersWithNix ./.) [
-        (map (name: {
-          inherit name;
-          path = path.append ./. "./${name}/default.nix";
-        }))
-        (map (
-          { name, path }:
-          {
-            inherit name;
-            value = pkgs.callPackage path {
-              inherit self;
-              inherit system;
-            };
-          }
-        ))
-        listToAttrs
-      ];
-    in
-    packages
-    // {
-      default =
-        let
-          nixosConfigs = mapAttrsToList (n: v: v.config.system.build.toplevel) self.nixosConfigurations;
-        in
-        pkgs.linkFarmFromDrvs "all" (nixosConfigs ++ (attrValues packages));
-    };
+  ${system} = genAttrs (foldersWithNix ./.) (
+    name:
+    pkgs.callPackage (path.append ./. "./${name}/default.nix") {
+      inherit
+        self
+        flakeSelf
+        system
+        private
+        ;
+    }
+  );
 }
diff --git a/packages/deploy-qois/default.nix b/packages/deploy-qois/default.nix
index ee3f0ac..ed647ef 100644
--- a/packages/deploy-qois/default.nix
+++ b/packages/deploy-qois/default.nix
@@ -1,6 +1,6 @@
 {
   deploy-rs,
-  self,
+  flakeSelf,
   writeShellApplication,
   ...
 }:
@@ -9,6 +9,6 @@ writeShellApplication {
   meta.description = "Deploy configuration to specificed targets.";
   runtimeInputs = [ deploy-rs ];
   text = ''
-    deploy --interactive --targets "''${@:-${self}}"
+    deploy --interactive --targets "''${@:-${flakeSelf}}"
   '';
 }
diff --git a/packages/docs/default.nix b/packages/docs/default.nix
index f16736d..66f7dd9 100644
--- a/packages/docs/default.nix
+++ b/packages/docs/default.nix
@@ -3,12 +3,12 @@
   mdbook-plantuml,
   mdbook,
   plantuml,
-  self,
+  flakeSelf,
   stdenv,
   ...
 }:
 let
-  version = self.rev or self.dirtyRev;
+  version = flakeSelf.rev or flakeSelf.dirtyRev;
 in
 stdenv.mkDerivation {
   inherit version;
@@ -19,6 +19,6 @@ stdenv.mkDerivation {
     mdbook-plantuml
     plantuml
   ];
-  src = self;
+  src = flakeSelf;
   buildPhase = "mdbook build --dest-dir $out";
 }
diff --git a/packages/sops-config/default.nix b/packages/sops-config/default.nix
index 1daf54a..0fc0344 100644
--- a/packages/sops-config/default.nix
+++ b/packages/sops-config/default.nix
@@ -3,7 +3,7 @@
   gnupg,
   lib,
   runCommand,
-  self,
+  private,
   ssh-to-age,
   writeText,
   ...
@@ -13,7 +13,7 @@ let
   metaHostConfigs = import ../../defaults/meta/hosts.nix { };
   userPgpKeys =
     let
-      keysFolder = "${self.inputs.private}/sops_keys";
+      keysFolder = "${private}/sops_keys";
       gpgFingerprintsFile =
         runCommand "userPgpKeys"
           {
diff --git a/private b/private
index 33cf800..f79080b 160000
--- a/private
+++ b/private
@@ -1 +1 @@
-Subproject commit 33cf80043c64ddd6882268430454e3cbe98b692b
+Subproject commit f79080b8802eec4463bb4a25c64f82f73e6e31db