diff --git a/artiq-board-generated/default.nix b/artiq-board-generated/default.nix
index 467c7b3..e63de29 100644
--- a/artiq-board-generated/default.nix
+++ b/artiq-board-generated/default.nix
@@ -1,9 +1,11 @@
 { pkgs ? import <nixpkgs> {}
 , artiq-fast ? <artiq-fast>
+, sinaraSystemsSrc ? <sinaraSystemsSrc>
+, sinaraSystemsRev ? null
+, sinaraSystemsHash ? null
 }:
 
 let
-  sinaraSystemsSrc = <sinaraSystemsSrc>;
   generatedNix = pkgs.runCommand "generated-nix" { buildInputs = [ pkgs.nix pkgs.git ]; }
     ''
     mkdir $out
@@ -11,14 +13,21 @@ let
     cp ${../artiq-full/artiq-targets.nix} $out/artiq-targets.nix
     cp -a ${artiq-fast} $out/fast
 
-    REV=`git --git-dir ${sinaraSystemsSrc}/.git rev-parse HEAD`
+    ${if sinaraSystemsRev != null && sinaraSystemsHash != null
+      then ''
+        REV=${sinaraSystemsRev}
+        HASH=${sinaraSystemsHash}
+      '' else ''
+        REV=`git --git-dir ${sinaraSystemsSrc}/.git rev-parse HEAD`
+        SINARA_SRC_CLEAN=`mktemp -d`
+        cp -a ${sinaraSystemsSrc}/. $SINARA_SRC_CLEAN
+        chmod -R 755 $SINARA_SRC_CLEAN/.git
+        chmod 755 $SINARA_SRC_CLEAN
+        rm -rf $SINARA_SRC_CLEAN/.git
+        HASH=`nix-hash --type sha256 --base32 $SINARA_SRC_CLEAN`
+      ''}
+
     echo -n $REV > $out/sinara-rev.txt
-    SINARA_SRC_CLEAN=`mktemp -d`
-    cp -a ${sinaraSystemsSrc}/. $SINARA_SRC_CLEAN
-    chmod -R 755 $SINARA_SRC_CLEAN/.git
-    chmod 755 $SINARA_SRC_CLEAN
-    rm -rf $SINARA_SRC_CLEAN/.git
-    HASH=`nix-hash --type sha256 --base32 $SINARA_SRC_CLEAN`
     echo -n $HASH > $out/sinara-hash.txt
 
     cat > $out/default.nix << EOF
diff --git a/artiq-fast/conda-windows/binutils.nix b/artiq-fast/conda-windows/binutils.nix
index 6358ebe..935c863 100644
--- a/artiq-fast/conda-windows/binutils.nix
+++ b/artiq-fast/conda-windows/binutils.nix
@@ -1,7 +1,10 @@
 { pkgs, version, src, target }:
 
 let
-  wfvm = import ../wfvm.nix { inherit pkgs; };
+  wfvm = import ../wfvm.nix {
+    inherit pkgs;
+    wfvm-pkgs = pkgs;
+  };
   libiconv-filename = "libiconv-1.15-h1df5818_7.tar.bz2";
   libiconv = pkgs.fetchurl {
     url = "https://anaconda.org/anaconda/libiconv/1.15/download/win-64/${libiconv-filename}";
diff --git a/artiq-fast/conda-windows/llvm-or1k.nix b/artiq-fast/conda-windows/llvm-or1k.nix
index e23140a..7b10666 100644
--- a/artiq-fast/conda-windows/llvm-or1k.nix
+++ b/artiq-fast/conda-windows/llvm-or1k.nix
@@ -1,7 +1,10 @@
 { pkgs, version, src }:
 
 let
-  wfvm = import ../wfvm.nix { inherit pkgs; };
+  wfvm = import ../wfvm.nix {
+    inherit pkgs;
+    wfvm-pkgs = pkgs;
+  };
   conda-vs2015_runtime-filename = "vs2015_runtime-14.16.27012-hf0eaf9b_2.tar.bz2";
   conda-vs2015_runtime = pkgs.fetchurl {
     url = "https://anaconda.org/anaconda/vs2015_runtime/14.16.27012/download/win-64/${conda-vs2015_runtime-filename}";
diff --git a/artiq-fast/conda-windows/llvmlite-artiq.nix b/artiq-fast/conda-windows/llvmlite-artiq.nix
index 51eaafc..b15ccd0 100644
--- a/artiq-fast/conda-windows/llvmlite-artiq.nix
+++ b/artiq-fast/conda-windows/llvmlite-artiq.nix
@@ -1,7 +1,10 @@
 { pkgs, conda-windows-llvm-or1k, version, src }:
 
 let
-  wfvm = import ../wfvm.nix { inherit pkgs; };
+  wfvm = import ../wfvm.nix {
+    inherit pkgs;
+    wfvm-pkgs = pkgs;
+  };
   conda-vs2015_runtime-filename = "vs2015_runtime-14.16.27012-hf0eaf9b_2.tar.bz2";
   conda-vs2015_runtime = pkgs.fetchurl {
     url = "https://anaconda.org/anaconda/vs2015_runtime/14.16.27012/download/win-64/${conda-vs2015_runtime-filename}";
diff --git a/artiq-fast/pkgs/llvm-or1k.nix b/artiq-fast/pkgs/llvm-or1k.nix
index b305485..fc6925e 100644
--- a/artiq-fast/pkgs/llvm-or1k.nix
+++ b/artiq-fast/pkgs/llvm-or1k.nix
@@ -33,8 +33,6 @@ in
     buildInputs = [ perl groff cmake libxml2 python libffi ] ++ stdenv.lib.optional stdenv.isLinux valgrind;
 
     preBuild = ''
-      NIX_BUILD_CORES=4
-      makeFlagsArray=(-j''$NIX_BUILD_CORES)
       mkdir -p $out/
     '';
 
diff --git a/artiq-fast/wfvm.nix b/artiq-fast/wfvm.nix
index a520492..e9df6b3 100644
--- a/artiq-fast/wfvm.nix
+++ b/artiq-fast/wfvm.nix
@@ -1,16 +1,16 @@
-{ pkgs }:
-
-let
-  # Pin nixpkgs to avoid frequent resource-intensive Windows reinstallations on Hydra.
-  wfvm-pkgs = pkgs.fetchFromGitHub {
+{ pkgs
+, wfvm-pkgs ? import (pkgs.fetchFromGitHub {
     owner = "NixOS";
     repo = "nixpkgs";
     rev = "f8248ab6d9e69ea9c07950d73d48807ec595e923";
     sha256 = "009i9j6mbq6i481088jllblgdnci105b2q4mscprdawg3knlyahk";
-  };
+  }) {}
+}:
+
+let
   wfvm = pkgs.fetchgit {
     url = "https://git.m-labs.hk/M-Labs/wfvm.git";
     rev = "4b497938ffd9fcddf84a3dbe2f01524395292adb";
     sha256 = "0m3kdbbcskqc1lf8b5f7ccbll9b7vkl4r00kbyx3yjb2rs6cqvil";
   };
-in import "${wfvm}/wfvm" { pkgs = (import wfvm-pkgs {}); }
+in import "${wfvm}/wfvm" { pkgs = wfvm-pkgs; }
diff --git a/artiq-fast/windows/make_conda_packages.sh b/artiq-fast/windows/make_conda_packages.sh
index d7336d8..f734380 100755
--- a/artiq-fast/windows/make_conda_packages.sh
+++ b/artiq-fast/windows/make_conda_packages.sh
@@ -13,7 +13,10 @@ set -e
 nix-build -E "
 let
   pkgs = import <nixpkgs> {};
-  wfvm = import ../wfvm.nix { inherit pkgs; };
+  wfvm = import ../wfvm.nix {
+    inherit pkgs;
+    wfvm-pkgs = pkgs;
+  };
 in
   wfvm.utils.wfvm-run {
     name = \"get-conda-packages\";
diff --git a/artiq-fast/windows/run-test.nix b/artiq-fast/windows/run-test.nix
index 5fc86f4..89b35a5 100644
--- a/artiq-fast/windows/run-test.nix
+++ b/artiq-fast/windows/run-test.nix
@@ -10,7 +10,10 @@ let
       inherit port;
     }) tcpPorts;
 
-  wfvm = import ../wfvm.nix { inherit pkgs; };
+  wfvm = import ../wfvm.nix {
+    inherit pkgs;
+    wfvm-pkgs = pkgs;
+  };
   conda-deps = {
     name = "conda-deps";
     script = let
diff --git a/artiq-full.nix b/artiq-full.nix
index 57b44cf..6110dc5 100644
--- a/artiq-full.nix
+++ b/artiq-full.nix
@@ -1,22 +1,25 @@
 { pkgs ? import <nixpkgs> {}
 , a6p ? <a6p>
+, artiq-board-generated ? <artiq-board-generated>
+, sinaraSystemsRev ? builtins.readFile (artiq-board-generated + "/sinara-rev.txt")
+, sinaraSystemsHash ? builtins.readFile (artiq-board-generated + "/sinara-hash.txt")
+, sinaraSystemsSrc ? (
+  if a6p
+  then pkgs.fetchgit {
+    url = "https://git.m-labs.hk/M-Labs/sinara-systems.git";
+    rev = sinaraSystemsRev;
+    sha256 = sinaraSystemsHash;
+  }
+  else <sinaraSystemsSrc>
+)
+, artiq-fast ? (
+  if a6p
+  then <artiq-board-generated/fast>
+  else <artiq-fast>
+)
 }:
 
 let
-  sinaraSystemsRev = builtins.readFile <artiq-board-generated/sinara-rev.txt>;
-  sinaraSystemsHash = builtins.readFile <artiq-board-generated/sinara-hash.txt>;
-  sinaraSystemsSrc =
-    if a6p
-    then pkgs.fetchgit {
-      url = "https://git.m-labs.hk/M-Labs/sinara-systems.git";
-      rev = sinaraSystemsRev;
-      sha256 = sinaraSystemsHash;
-    }
-    else <sinaraSystemsSrc>;
-  artiq-fast =
-    if a6p
-    then <artiq-board-generated/fast>
-    else <artiq-fast>;
   artiqVersion = import (artiq-fast + "/pkgs/artiq-version.nix") {
     inherit (pkgs) stdenv git fetchgit;
   };
@@ -49,17 +52,17 @@ let
 
     ${if a6p
       then ''
-        cp -a ${<artiq-board-generated>} $out/board-generated
+        cp -a ${artiq-board-generated} $out/board-generated
         ln -s board-generated/fast $out/fast
       ''
-      else "cp -a ${<artiq-fast>} $out/fast"}
+      else "cp -a ${artiq-fast} $out/fast"}
     cp ${./artiq-full}/artiq-board-vivado.nix $out
     cp ${./artiq-full}/generate-identifier.py $out
     cp ${./artiq-full}/conda-artiq-board.nix $out
     cp ${./artiq-full}/extras.nix $out
     cp ${./artiq-full}/*.patch $out
 
-    ${if a6p
+    ${if sinaraSystemsRev != null && sinaraSystemsHash != null
       then ''
         REV=${sinaraSystemsRev}
         HASH=${sinaraSystemsHash}
@@ -109,7 +112,9 @@ let
             inherit pkgs vivado;
           }
         ''};
-      conda-artiq-board = import ./conda-artiq-board.nix { inherit pkgs; };
+      conda-artiq-board = import ./conda-artiq-board.nix {
+        inherit pkgs;
+      };
       src = pkgs.fetchgit {
         url = "https://git.m-labs.hk/M-Labs/sinara-systems.git";
         rev = "$REV";
diff --git a/flake.lock b/flake.lock
new file mode 100644
index 0000000..2f8ef43
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,97 @@
+{
+  "nodes": {
+    "artiq-beta-src": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1614493604,
+        "narHash": "sha256-9P/O4SWHqHWO+OD3d8FihJXQ+Y5JRlW0ajBNYZlIZUg=",
+        "ref": "master",
+        "rev": "b8f4c6b9bb8ce4f2d7dc50e87690ad336841357c",
+        "revCount": 7585,
+        "type": "git",
+        "url": "https://github.com/M-Labs/artiq.git"
+      },
+      "original": {
+        "type": "git",
+        "url": "https://github.com/M-Labs/artiq.git"
+      }
+    },
+    "artiq-legacy-src": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1613549523,
+        "narHash": "sha256-FgX/W+y8N4/6DLLTJuJVg5gUr3zk/5DxmSIxA4I6ZvE=",
+        "ref": "release-5",
+        "rev": "10c9842fc8844b524811336c6a529c648a2d2fde",
+        "revCount": 7153,
+        "type": "git",
+        "url": "https://github.com/M-Labs/artiq.git"
+      },
+      "original": {
+        "ref": "release-5",
+        "type": "git",
+        "url": "https://github.com/M-Labs/artiq.git"
+      }
+    },
+    "artiq-src": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1613555154,
+        "narHash": "sha256-D/43YVvMNkcXV6sBBxAqxcmtEO3TagIQEQl0zsGE+ag=",
+        "ref": "release-6",
+        "rev": "c22482787ef806eb8e48d59b6ded7d93c7677c81",
+        "revCount": 7582,
+        "type": "git",
+        "url": "https://github.com/M-Labs/artiq.git"
+      },
+      "original": {
+        "ref": "release-6",
+        "type": "git",
+        "url": "https://github.com/M-Labs/artiq.git"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1614338965,
+        "narHash": "sha256-2HPgL9171Dhlg9lS4Ep5aeh4ejRCED+gNmU9tYzgyic=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "113092f5531ef38a45046990199873755a372646",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "release-20.09",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "artiq-beta-src": "artiq-beta-src",
+        "artiq-legacy-src": "artiq-legacy-src",
+        "artiq-src": "artiq-src",
+        "nixpkgs": "nixpkgs",
+        "sinara-systems": "sinara-systems"
+      }
+    },
+    "sinara-systems": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1615195806,
+        "narHash": "sha256-UfsPJxvERsGiECOFC+sjmk4r61aWepF0nXqRgnmLR80=",
+        "ref": "master",
+        "rev": "1f0605f46cc7cbfcdf427f15a93e0e4a75d0d491",
+        "revCount": 202,
+        "type": "git",
+        "url": "https://git.m-labs.hk/M-Labs/sinara-systems.git"
+      },
+      "original": {
+        "type": "git",
+        "url": "https://git.m-labs.hk/M-Labs/sinara-systems.git"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000..6b75b9b
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,115 @@
+# let
+#   system = "x86_64-linux";
+# in
+{
+  description = "ARTIQ";
+
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/release-20.09";
+    artiq-beta-src = {
+      url = "git+https://github.com/M-Labs/artiq.git";
+      flake = false;
+    };
+    artiq-src = {
+      url = "git+https://github.com/M-Labs/artiq.git?ref=release-6";
+      flake = false;
+    };
+    artiq-legacy-src = {
+      url = "git+https://github.com/M-Labs/artiq.git?ref=release-5";
+      flake = false;
+    };
+    sinara-systems = {
+      url = "git+https://git.m-labs.hk/M-Labs/sinara-systems.git";
+      flake = false;
+    };
+  };
+
+  outputs = sources@{ self, nixpkgs, sinara-systems, ... }:
+    let
+      systems = [
+        "x86_64-linux"
+      ];
+      forAllSystems = nixpkgs.lib.genAttrs systems;
+
+      sinaraSystemsSrc = sinara-systems.outPath;
+      sinaraSystemsRev = sinara-systems.rev;
+      sinaraSystemsHash = builtins.replaceStrings ["sha256-"] [""] sinara-systems.narHash;
+
+      artiq-jobsets = system: artiqInputName: a6p:
+        let
+          pkgs = nixpkgs.legacyPackages.${system};
+
+          artiq-fast-src =
+            let
+              inherit (sources.${artiqInputName}) lastModified rev revCount narHash;
+              hash = builtins.replaceStrings ["sha256-"] [""] narHash;
+
+              artiqSrc = sources.${artiqInputName}.outPath;
+
+            in pkgs.runCommand "generated-nix" { buildInputs = [ pkgs.nix pkgs.git ]; } ''
+                cp --no-preserve=mode,ownership -R ${./artiq-fast} $out
+
+                MAJOR_VERSION=`cat ${artiqSrc}/MAJOR_VERSION`
+                if [ -e ${artiqSrc}/BETA ]; then
+                  SUFFIX=".beta"
+                else
+                  SUFFIX=""
+                fi
+
+                cat > $out/pkgs/artiq-src.nix << EOF
+                { fetchgit }:
+                fetchgit {
+                  url = "git://github.com/m-labs/artiq.git";
+                  rev = "${rev}";
+                  sha256 = "${hash}";
+                }
+                EOF
+                echo "{ stdenv, git, fetchgit }: \"$MAJOR_VERSION.${toString revCount}.`cut -c1-8 <<< ${rev}`$SUFFIX\"" > $out/pkgs/artiq-version.nix
+                echo "{ stdenv, git, fetchgit }: \"${toString lastModified}\"" > $out/pkgs/artiq-timestamp.nix
+            '';
+          artiq-fast =
+            import artiq-fast-src {
+              inherit pkgs;
+            };
+
+          artiq-board-generated =
+            (import ./artiq-board-generated {
+              inherit pkgs;
+              inherit sinaraSystemsSrc sinaraSystemsRev sinaraSystemsHash;
+              artiq-fast = artiq-fast-src;
+            }).generated-nix;
+
+          artiq-full =
+            import ./artiq-full.nix {
+              inherit pkgs a6p artiq-board-generated;
+              artiq-fast = artiq-fast-src;
+              inherit sinaraSystemsSrc sinaraSystemsRev sinaraSystemsHash;
+            };
+        in {
+          inherit artiq-fast artiq-full;
+        };
+    in {
+      packages = forAllSystems (system:
+        builtins.foldl' (a: b: a // b) {} (
+          builtins.attrValues (
+            artiq-jobsets system "artiq-beta-src" true
+          )
+        )
+      );
+
+      defaultPackage = forAllSystems (system: self.packages.${system}.artiq);
+
+      hydraJobs =
+        let
+          jobset = artiqInputName: a6p: name:
+            forAllSystems (system: (artiq-jobsets system artiqInputName a6p).${name});
+        in {
+          fast = jobset "artiq-src" true "artiq-fast";
+          fast-beta = jobset "artiq-beta-src" true "artiq-fast";
+          fast-legacy = jobset "artiq-legacy-src" false "artiq-fast";
+          full = jobset "artiq-src" true "artiq-full";
+          full-beta = jobset "artiq-beta-src" true "artiq-full";
+          full-legacy = jobset "artiq-legacy-src" false "artiq-full";
+        };
+    };
+}