diff --git a/README.md b/README.md
index 4b8e9c8..9dbd617 100644
--- a/README.md
+++ b/README.md
@@ -28,21 +28,14 @@ How to use
 Install a Windows image
 -----------------------
 
-1. Adjust demo-image.nix accordingly
+1. Adjust demo-image in ``flake.nix`` accordingly
 2. Run:
 
-If in impure mode
 ```shell
-nix-build demo-image.nix
+nix build .#demo-image
 ./result
 ```
-Results in a file called c.img
 
-If in pure mode
-```shell
-nix-build demo-image.nix
-ls -la ./result
-```
 Results in a symlink to the image in the nix store
 
 
@@ -52,3 +45,5 @@ Impure/pure mode
 Sometimes it can be useful to build the image _outside_ of the Nix sandbox for debugging purposes.
 
 For this purpose we have an attribute called `impureMode` which outputs the shell script used by Nix inside the sandbox to build the image.
+
+When building an image with flakes, use ``nix build .#demo-image-impure`` instead.
\ No newline at end of file
diff --git a/flake.lock b/flake.lock
new file mode 100644
index 0000000..4f34ad6
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,27 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1593034146,
+        "narHash": "sha256-EypP7RyPq5Yv05VgsQoIkdn26KJUIgQCItHgVY1MMQE=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "f8248ab6d9e69ea9c07950d73d48807ec595e923",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "f8248ab6d9e69ea9c07950d73d48807ec595e923",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000..c52e4c1
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,129 @@
+{
+  description = "A Nix library to create and manage virtual machines running Windows.";
+  inputs.nixpkgs.url = github:NixOS/nixpkgs/f8248ab6d9e69ea9c07950d73d48807ec595e923;
+  outputs = { self, nixpkgs }:
+    let
+      pkgs = import nixpkgs { system = "x86_64-linux"; };
+      lib = pkgs.lib;
+      # utils
+      utils = (import wfvm/utils.nix { inherit pkgs; });
+      # layers
+      layers = (import wfvm/layers { inherit pkgs; }); # end of layers
+
+
+
+    # makeWindowsImage 
+    makeWindowsImage = attrs: import wfvm/win.nix ({ inherit pkgs; } // attrs );
+
+    build-demo-image = { impureMode ? false }: makeWindowsImage {
+          # Build install script & skip building iso
+
+          inherit impureMode;
+
+          # Custom base iso
+          # windowsImage = pkgs.requireFile rec {
+          #   name = "Win10_21H1_English_x64.iso";
+          #   sha256 = "1sl51lnx4r6ckh5fii7m2hi15zh8fh7cf7rjgjq9kacg8hwyh4b9";
+          #   message = "Get ${name} from https://www.microsoft.com/en-us/software-download/windows10ISO";
+          # };
+
+          # impureShellCommands = [
+          #   "powershell.exe echo Hello"
+          # ];
+
+          # User accounts
+          # users = {
+          #   artiq = {
+          #     password = "1234";
+          #     # description = "Default user";
+          #     # displayName = "Display name";
+          #     groups = [
+          #       "Administrators"
+          #     ];
+          #   };
+          # };
+
+          # Auto login
+          # defaultUser = "artiq";
+
+          # fullName = "M-Labs";
+          # organization = "m-labs";
+          # administratorPassword = "12345";
+
+          # Imperative installation commands, to be installed incrementally
+          installCommands = if impureMode then [] else (with layers; [
+              (collapseLayers [
+                disable-autosleep
+                disable-autolock
+                disable-firewall
+              ])
+              anaconda3 msys2 msvc msvc-ide-unbreak
+            ]);
+
+          # services = {
+          #   # Enable remote management
+          #   WinRm = {
+          #     Status = "Running";
+          #     PassThru = true;
+          #   };
+          # };
+
+          # License key (required)
+          # productKey = throw "Search the f* web"
+          # imageSelection = "1";
+
+          # Locales
+          # uiLanguage = "en-US";
+          # inputLocale = "en-US";
+          # userLocale = "en-US";
+          # systemLocale = "en-US";
+        };
+
+    in {
+
+      # bundle dev env
+      devShell.x86_64-linux = pkgs.mkShell {
+        name = "wfvm-dev-shell";
+        buildInputs = with pkgs; [
+          go
+        ];
+        shellHook = ''
+          unset GOPATH
+        '';
+      };
+
+      inherit utils;
+      inherit makeWindowsImage;
+      inherit layers;
+
+      demo-ssh = utils.wfvm-run {
+        name = "demo-ssh";
+        image = build-demo-image {};
+        isolateNetwork = false;
+        script = ''
+          ${pkgs.sshpass}/bin/sshpass -p1234 -- ${pkgs.openssh}/bin/ssh -p 2022 wfvm@localhost -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null
+        '';
+      };
+
+      packages.x86_64-linux = {
+        demo-image = build-demo-image {};
+        demo-image-impure = build-demo-image { impureMode = true; };
+
+        make-msys-packages = utils.wfvm-run {
+          name = "get-msys-packages";
+          image = makeWindowsImage { installCommands = [ layers.msys2 ]; };
+          script = ''
+            cat > getmsyspackages.bat << EOF
+            set MSYS=C:\\MSYS64
+            set TOOLPREF=mingw-w64-x86_64-
+            set PATH=%MSYS%\usr\bin;%MSYS%\mingw64\bin;%PATH%
+            pacman -Sp %TOOLPREF%gcc %TOOLPREF%binutils make autoconf automake libtool texinfo > packages.txt
+            EOF
+            \${utils.win-put}/bin/win-put getmsyspackages.bat
+            \${utils.win-exec}/bin/win-exec getmsyspackages
+            \${utils.win-get}/bin/win-get packages.txt
+          '';
+        };
+      };
+    };
+}
\ No newline at end of file
diff --git a/wfvm/autounattend.nix b/wfvm/autounattend.nix
index 99b0429..abd1c16 100644
--- a/wfvm/autounattend.nix
+++ b/wfvm/autounattend.nix
@@ -15,7 +15,7 @@
 , impureShellCommands ? []
 , driveLetter ? "D:"
 , efi ? true
-, imageSelection ? "Windows 10 Pro"
+, imageSelection ? "1"
 , ...
 }:
 
@@ -200,7 +200,7 @@ let
               </InstallTo>
               <InstallFrom>
                 <MetaData wcm:action="add">
-                  <Key>/IMAGE/NAME</Key>
+                  <Key>/IMAGE/INDEX</Key>
                   <Value>${imageSelection}</Value>
                 </MetaData>
               </InstallFrom>
diff --git a/wfvm/bundle/default.nix b/wfvm/bundle/default.nix
deleted file mode 100644
index 16a0fed..0000000
--- a/wfvm/bundle/default.nix
+++ /dev/null
@@ -1,10 +0,0 @@
-{ pkgs }:
-
-pkgs.runCommandNoCC "win-bundle-installer.exe" {} ''
-  mkdir bundle
-  cd bundle
-  cp ${./go.mod} go.mod
-  cp ${./main.go} main.go
-  env HOME=$(mktemp -d) GOOS=windows GOARCH=amd64 ${pkgs.go}/bin/go build
-  mv bundle.exe $out
-''
diff --git a/wfvm/bundle/shell.nix b/wfvm/bundle/shell.nix
deleted file mode 100644
index 20c60ed..0000000
--- a/wfvm/bundle/shell.nix
+++ /dev/null
@@ -1,13 +0,0 @@
-{ pkgs ? import <nixpkgs> {} }:
-
-pkgs.mkShell {
-
-  buildInputs = [
-    pkgs.go
-  ];
-
-  shellHook = ''
-    unset GOPATH
-  '';
-
-}
diff --git a/wfvm/default.nix b/wfvm/default.nix
deleted file mode 100644
index 7846583..0000000
--- a/wfvm/default.nix
+++ /dev/null
@@ -1,7 +0,0 @@
-{ pkgs }:
-
-{
-  makeWindowsImage = attrs: import ./win.nix ({ inherit pkgs; } // attrs);
-  layers = (import ./layers { inherit pkgs; });
-  utils = (import ./utils.nix { inherit pkgs; });
-}
diff --git a/wfvm/demo-image.nix b/wfvm/demo-image.nix
deleted file mode 100644
index a928de1..0000000
--- a/wfvm/demo-image.nix
+++ /dev/null
@@ -1,72 +0,0 @@
-{ pkgs ? import <nixpkgs> {}, impureMode ? false }:
-
-let
-  wfvm = (import ./default.nix { inherit pkgs; });
-in
-wfvm.makeWindowsImage {
-  # Build install script & skip building iso
-  inherit impureMode;
-
-  # Custom base iso
-  # windowsImage = pkgs.requireFile rec {
-  #   name = "Win10_21H1_English_x64.iso";
-  #   sha256 = "1sl51lnx4r6ckh5fii7m2hi15zh8fh7cf7rjgjq9kacg8hwyh4b9";
-  #   message = "Get ${name} from https://www.microsoft.com/en-us/software-download/windows10ISO";
-  # };
-
-  # impureShellCommands = [
-  #   "powershell.exe echo Hello"
-  # ];
-
-  # User accounts
-  # users = {
-  #   artiq = {
-  #     password = "1234";
-  #     # description = "Default user";
-  #     # displayName = "Display name";
-  #     groups = [
-  #       "Administrators"
-  #     ];
-  #   };
-  # };
-
-  # Auto login
-  # defaultUser = "artiq";
-
-  # fullName = "M-Labs";
-  # organization = "m-labs";
-  # administratorPassword = "12345";
-
-  # Imperative installation commands, to be installed incrementally
-  installCommands =
-    if impureMode
-    then []
-    else with wfvm.layers; [
-      (collapseLayers [
-        disable-autosleep
-        disable-autolock
-        disable-firewall
-      ])
-      anaconda3 msys2 msvc msvc-ide-unbreak
-    ];
-
-  # services = {
-  #   # Enable remote management
-  #   WinRm = {
-  #     Status = "Running";
-  #     PassThru = true;
-  #   };
-  # };
-
-  # License key (required)
-  # productKey = throw "Search the f* web"
-  imageSelection = "Windows 10 Pro";
-
-
-  # Locales
-  # uiLanguage = "en-US";
-  # inputLocale = "en-US";
-  # userLocale = "en-US";
-  # systemLocale = "en-US";
-
-}
diff --git a/wfvm/demo-ssh.nix b/wfvm/demo-ssh.nix
deleted file mode 100644
index 47c60e4..0000000
--- a/wfvm/demo-ssh.nix
+++ /dev/null
@@ -1,13 +0,0 @@
-{ pkgs ? import <nixpkgs> {} }:
-
-let
-  wfvm = (import ./default.nix { inherit pkgs; });
-in
-  wfvm.utils.wfvm-run {
-    name = "demo-ssh";
-    image = import ./demo-image.nix { inherit pkgs; };
-    isolateNetwork = false;
-    script = ''
-      ${pkgs.sshpass}/bin/sshpass -p1234 -- ${pkgs.openssh}/bin/ssh -p 2022 wfvm@localhost -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null
-    '';
-  }
diff --git a/wfvm/layers/default.nix b/wfvm/layers/default.nix
index a9068a6..ec20fd3 100644
--- a/wfvm/layers/default.nix
+++ b/wfvm/layers/default.nix
@@ -1,6 +1,7 @@
 { pkgs }:
 let
-  wfvm = import ../. { inherit pkgs; };
+  makeWindowsImage =  attrs: import ../win.nix ({ inherit pkgs; } // attrs );
+  utils = import ../utils.nix { inherit pkgs; };
 in
 {
   anaconda3 = {
@@ -72,20 +73,20 @@ in
       bootstrapper = pkgs.fetchurl {
         name = "RESTRICTDIST-vs_Community.exe";
         url = "https://aka.ms/vs/16/release/vs_community.exe";
-        sha256 = "0b3csxz0qsafnvc0d74ywfpralwz8chv4zf9k07akpm8lp8ycgq0";
+        sha256 = "sha256-bxi8LsvNxSZshkTbhK/FEmMx84NKYB7TUNOm9sAKXS8=";
       };
       # This touchy-feely "community" piece of trash seems deliberately crafted to break Wine, so we use the VM to run it.
-      download-vs = wfvm.utils.wfvm-run {
+      download-vs = utils.wfvm-run {
         name = "download-vs";
-        image = wfvm.makeWindowsImage { };
+        image = makeWindowsImage { };
         isolateNetwork = false;
         script =
           ''
           ln -s ${bootstrapper} vs_Community.exe
-          ${wfvm.utils.win-put}/bin/win-put vs_Community.exe
+          ${utils.win-put}/bin/win-put vs_Community.exe
           rm vs_Community.exe
-          ${wfvm.utils.win-exec}/bin/win-exec "vs_Community.exe --quiet --norestart --layout c:\vslayout --add Microsoft.VisualStudio.Workload.NativeDesktop --includeRecommended --lang en-US"
-          ${wfvm.utils.win-get}/bin/win-get /c:/vslayout
+          ${utils.win-exec}/bin/win-exec "vs_Community.exe --quiet --norestart --layout c:\vslayout --add Microsoft.VisualStudio.Workload.NativeDesktop --includeRecommended --lang en-US"
+          ${utils.win-get}/bin/win-get /c:/vslayout
           '';
       };
       cache = pkgs.stdenv.mkDerivation {
diff --git a/wfvm/layers/make_msys_packages.sh b/wfvm/layers/make_msys_packages.sh
index fa8595e..ef39678 100755
--- a/wfvm/layers/make_msys_packages.sh
+++ b/wfvm/layers/make_msys_packages.sh
@@ -2,27 +2,7 @@
 
 set -e
 
-nix-build -E "
-let
-  pkgs = import <nixpkgs> {};
-  wfvm = import ../default.nix { inherit pkgs; };
-in
-  wfvm.utils.wfvm-run {
-    name = \"get-msys-packages\";
-    image = wfvm.makeWindowsImage { installCommands = [ wfvm.layers.msys2 ]; };
-    script = ''
-      cat > getmsyspackages.bat << EOF
-      set MSYS=C:\\MSYS64
-      set TOOLPREF=mingw-w64-x86_64-
-      set PATH=%MSYS%\usr\bin;%MSYS%\mingw64\bin;%PATH%
-      pacman -Sp %TOOLPREF%gcc %TOOLPREF%binutils make autoconf automake libtool texinfo > packages.txt
-      EOF
-      \${wfvm.utils.win-put}/bin/win-put getmsyspackages.bat
-      \${wfvm.utils.win-exec}/bin/win-exec getmsyspackages
-      \${wfvm.utils.win-get}/bin/win-get packages.txt
-    '';
-  }
-"
+nix build .#make-msys-packages
 
 ./result/bin/wfvm-run-get-msys-packages
 
diff --git a/wfvm/win.nix b/wfvm/win.nix
index 0e153e4..cd265f4 100644
--- a/wfvm/win.nix
+++ b/wfvm/win.nix
@@ -8,6 +8,7 @@
 # autounattend always installs index 1, so this default is backward-compatible
 , imageSelection ? "Windows 10 Pro"
 , efi ? true
+, bundleInstaller ? {}
 , ...
 }@attrs:
 
@@ -23,6 +24,16 @@ let
     };
   });
 
+  # bundle
+  bundleInstaller = pkgs.runCommandNoCC "win-bundle-installer.exe" {} ''
+    mkdir bundle
+    cd bundle
+    cp ${bundle/go.mod} go.mod
+    cp ${bundle/main.go} main.go
+    env HOME=$(mktemp -d) GOOS=windows GOARCH=amd64 ${pkgs.go}/bin/go build
+    mv bundle.exe $out
+  '';
+
   runQemuCommand = name: command: (
     pkgs.runCommandNoCC name { buildInputs = [ p7zip utils.qemu libguestfs ]; }
       (
@@ -36,8 +47,8 @@ let
   );
 
   windowsIso = if windowsImage != null then windowsImage else pkgs.requireFile rec {
-    name = "Win10_21H1_English_x64.iso";
-    sha256 = "1sl51lnx4r6ckh5fii7m2hi15zh8fh7cf7rjgjq9kacg8hwyh4b9";
+    name = "xks67i4frg8k7rmlv5298aac0s4n5nih-RESTRICTDIST-release_svc_refresh_CLIENT_LTSC_EVAL_x64FRE_en-us.iso";
+    sha256 = "0fmw30g7959bh47z8xi5pmmxq4kb0sxs1qxf51il3xy2f2py33v6";
     message = "Get ${name} from https://www.microsoft.com/en-us/software-download/windows10ISO";
   };
 
@@ -67,8 +78,6 @@ let
     }
   );
 
-  bundleInstaller = pkgs.callPackage ./bundle {};
-
   # Packages required to drive installation of other packages
   bootstrapPkgs =
     runQemuCommand "bootstrap-win-pkgs.img" ''