diff --git a/README.md b/README.md
index f2e6d47..53a9022 100644
--- a/README.md
+++ b/README.md
@@ -6,29 +6,17 @@ Minimalist bare metal Rust firmware for Red Pitaya.
 Development instructions
 ------------------------
 
-Configure Nix channels:
-
-```shell
-nix-channel --add https://nixbld.m-labs.hk/channel/custom/artiq/fast-beta/artiq-fast
-nix-channel --update
-```
-
-Notes:
-
-- Rust Pitaya does not depend on ARTIQ but uses some packages available in the ARTIQ channel.
-- If you are using Nix channels the first time, you need to be aware of this bug: https://github.com/NixOS/nix/issues/3831.
-
 Pure build with Nix and execution on a remote JTAG server:
 
 ```shell
-nix-build -A rust-pitaya-jtag
+nix build .#rust-pitaya-jtag
 ./remote_run.sh
 ```
 
 Impure incremental build and execution on a remote JTAG server:
 
 ```shell
-nix-shell
+nix develop
 cd src
 gateware/rust-pitaya.py -g ../build/gateware  # build gateware
 make                                          # build firmware
@@ -38,14 +26,13 @@ cd ..
 
 Notes:
 
-- This is developed with Nixpkgs 20.09, and the ``nixbld.m-labs.hk`` binary substituter can also be used here (see the ARTIQ manual for the public key and instructions).
 - The impure build process is also compatible with non-Nix systems.
 - If the board is connected to the local machine, use the ``local_run.sh`` script.
 
 License
 -------
 
-Copyright (C) 2019-2020 M-Labs Limited.
+Copyright (C) 2019-2022 M-Labs Limited.
 
 Rust Pitaya is free software: you can redistribute it and/or modify
 it under the terms of the GNU Lesser General Public License as published by
diff --git a/default.nix b/default.nix
deleted file mode 100644
index 37f57e4..0000000
--- a/default.nix
+++ /dev/null
@@ -1,87 +0,0 @@
-let
-  zynq-rs = (import ./zynq-rs.nix);
-  pkgs = import <nixpkgs> { overlays = [ (import "${zynq-rs}/nix/mozilla-overlay.nix") ]; };
-  rustPlatform = (import "${zynq-rs}/nix/rust-platform.nix" { inherit pkgs; });
-  cargo-xbuild = (import zynq-rs).cargo-xbuild;
-  redpitaya-szl = (import zynq-rs).redpitaya-szl;
-  mkbootimage = import "${zynq-rs}/nix/mkbootimage.nix" { inherit pkgs; };
-  artiqpkgs = import <artiq-fast/default.nix> { inherit pkgs; };
-  vivado = import <artiq-fast/vivado.nix> { inherit pkgs; };
-in rec {
-  rust-pitaya-firmware = rustPlatform.buildRustPackage {
-    name = "rust-pitaya-firmware";
-
-    src = ./src;
-    cargoSha256 = "173013gdlk8mljps6lar892zqgxrmxa7fkv8is3wgvgf7dnifjzs";
-
-    nativeBuildInputs = [
-      pkgs.gnumake
-      (pkgs.python3.withPackages(ps: (with artiqpkgs; [ migen migen-axi misoc ])))
-      cargo-xbuild
-      pkgs.llvmPackages_9.llvm
-      pkgs.llvmPackages_9.clang-unwrapped
-    ];
-    buildPhase = ''
-      export XARGO_RUST_SRC="${rustPlatform.rust.rustc.src}/library"
-      export CARGO_HOME=$(mktemp -d cargo-home.XXX)
-      make
-    '';
-
-    installPhase = ''
-      mkdir -p $out $out/nix-support
-      cp ../build/firmware.bin $out/firmware.bin
-      cp ../build/firmware/armv7-none-eabihf/release/firmware $out/firmware.elf
-      echo file binary-dist $out/firmware.bin >> $out/nix-support/hydra-build-products
-      echo file binary-dist $out/firmware.elf >> $out/nix-support/hydra-build-products
-    '';
-
-    doCheck = false;
-    dontFixup = true;
-  };
-  rust-pitaya-gateware = pkgs.runCommand "rust-pitaya-gateware"
-    {
-      nativeBuildInputs = [ 
-        (pkgs.python3.withPackages(ps: (with artiqpkgs; [ migen migen-axi misoc ])))
-        vivado
-      ];
-    }
-    ''
-      python ${./src/gateware}/rust-pitaya.py -g build
-      mkdir -p $out $out/nix-support
-      cp build/top.bit $out
-      echo file binary-dist $out/top.bit >> $out/nix-support/hydra-build-products
-    '';
-
-
-  rust-pitaya-jtag = pkgs.runCommand "rust-pitaya-jtag" {}
-    ''
-      mkdir $out
-      ln -s ${redpitaya-szl}/szl.elf $out
-      ln -s ${rust-pitaya-firmware}/firmware.bin $out
-      ln -s ${rust-pitaya-gateware}/top.bit $out
-    '';
-  rust-pitaya-sd = pkgs.runCommand "rust-pitaya-sd"
-    {
-      buildInputs = [ mkbootimage ];
-    }
-    ''
-    # Do not use "long" paths in boot.bif, because embedded developers
-    # can't write software (mkbootimage will segfault).
-    bifdir=`mktemp -d`
-    cd $bifdir
-    ln -s ${redpitaya-szl}/szl.elf szl.elf
-    ln -s ${rust-pitaya-firmware}/firmware.elf firmware.elf
-    ln -s ${rust-pitaya-gateware}/top.bit top.bit
-    cat > boot.bif << EOF
-    the_ROM_image:
-    {
-      [bootloader]szl.elf
-      top.bit
-      firmware.elf
-    }
-    EOF
-    mkdir $out $out/nix-support
-    mkbootimage boot.bif $out/boot.bin
-    echo file binary-dist $out/boot.bin >> $out/nix-support/hydra-build-products
-    '';
-}
diff --git a/flake.lock b/flake.lock
new file mode 100644
index 0000000..976bb59
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,241 @@
+{
+  "nodes": {
+    "artiq": {
+      "inputs": {
+        "artiq-comtools": "artiq-comtools",
+        "mozilla-overlay": "mozilla-overlay",
+        "nixpkgs": "nixpkgs",
+        "sipyco": "sipyco",
+        "src-migen": "src-migen",
+        "src-misoc": "src-misoc",
+        "src-pythonparser": "src-pythonparser"
+      },
+      "locked": {
+        "lastModified": 1661404661,
+        "narHash": "sha256-j3l/plOlK2Hcd4XIC32PDfKvqUY8Apr9sBeczyJ/L8A=",
+        "ref": "master",
+        "rev": "b705862ecd014b0c3b69051c1c822f13ce8aeea2",
+        "revCount": 8144,
+        "type": "git",
+        "url": "https://github.com/m-labs/artiq.git"
+      },
+      "original": {
+        "type": "git",
+        "url": "https://github.com/m-labs/artiq.git"
+      }
+    },
+    "artiq-comtools": {
+      "inputs": {
+        "nixpkgs": [
+          "artiq-zynq",
+          "artiq",
+          "nixpkgs"
+        ],
+        "sipyco": [
+          "artiq-zynq",
+          "artiq",
+          "sipyco"
+        ]
+      },
+      "locked": {
+        "lastModified": 1654007592,
+        "narHash": "sha256-vaDFhE1ItjqtIcinC/6RAJGbj44pxxMUEeQUa3FtgEE=",
+        "owner": "m-labs",
+        "repo": "artiq-comtools",
+        "rev": "cb73281154656ee8f74db1866859e31bf42755cd",
+        "type": "github"
+      },
+      "original": {
+        "owner": "m-labs",
+        "repo": "artiq-comtools",
+        "type": "github"
+      }
+    },
+    "artiq-zynq": {
+      "inputs": {
+        "artiq": "artiq",
+        "mozilla-overlay": "mozilla-overlay_2",
+        "zynq-rs": "zynq-rs"
+      },
+      "locked": {
+        "lastModified": 1661774127,
+        "narHash": "sha256-OTJKLZBoJtisDcpjckMsq2PgtgrkwSm5VV51kOPS8yI=",
+        "ref": "master",
+        "rev": "38f4d6cd2e7a0c2122bff674e04d4c251fc76b3b",
+        "revCount": 576,
+        "type": "git",
+        "url": "https://git.m-labs.hk/m-labs/artiq-zynq"
+      },
+      "original": {
+        "type": "git",
+        "url": "https://git.m-labs.hk/m-labs/artiq-zynq"
+      }
+    },
+    "mozilla-overlay": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1657214286,
+        "narHash": "sha256-rO/4oymKXU09wG2bcTt4uthPCp1XsBZjxuCJo3yVXNs=",
+        "owner": "mozilla",
+        "repo": "nixpkgs-mozilla",
+        "rev": "0508a66e28a5792fdfb126bbf4dec1029c2509e0",
+        "type": "github"
+      },
+      "original": {
+        "owner": "mozilla",
+        "repo": "nixpkgs-mozilla",
+        "type": "github"
+      }
+    },
+    "mozilla-overlay_2": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1657214286,
+        "narHash": "sha256-rO/4oymKXU09wG2bcTt4uthPCp1XsBZjxuCJo3yVXNs=",
+        "owner": "mozilla",
+        "repo": "nixpkgs-mozilla",
+        "rev": "0508a66e28a5792fdfb126bbf4dec1029c2509e0",
+        "type": "github"
+      },
+      "original": {
+        "owner": "mozilla",
+        "repo": "nixpkgs-mozilla",
+        "type": "github"
+      }
+    },
+    "mozilla-overlay_3": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1650459918,
+        "narHash": "sha256-sroCK+QJTmoXtcRkwZyKOP9iAYOPID2Bwdxn4GkG16w=",
+        "owner": "mozilla",
+        "repo": "nixpkgs-mozilla",
+        "rev": "e1f7540fc0a8b989fb8cf701dc4fd7fc76bcf168",
+        "type": "github"
+      },
+      "original": {
+        "owner": "mozilla",
+        "repo": "nixpkgs-mozilla",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1657123678,
+        "narHash": "sha256-cowVkScfUPlbBXUp08MeVk/wgm9E1zp1uC+9no2hZYw=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "316b762afdb9e142a803f29c49a88b4a47db80ee",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-22.05",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "artiq-zynq": "artiq-zynq"
+      }
+    },
+    "sipyco": {
+      "inputs": {
+        "nixpkgs": [
+          "artiq-zynq",
+          "artiq",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1654830914,
+        "narHash": "sha256-tratXcWu6Dgzd0Qd9V6EMjuNlE9qDN1pKFhP+Gt0b64=",
+        "owner": "m-labs",
+        "repo": "sipyco",
+        "rev": "58b0935f7ae47659abee5b5792fa594153328d6f",
+        "type": "github"
+      },
+      "original": {
+        "owner": "m-labs",
+        "repo": "sipyco",
+        "type": "github"
+      }
+    },
+    "src-migen": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1656649178,
+        "narHash": "sha256-A91sZRrprEuPOtIUVxm6wX5djac9wnNZQ4+cU1nvJPc=",
+        "owner": "m-labs",
+        "repo": "migen",
+        "rev": "0fb91737090fe45fd764ea3f71257a4c53c7a4ae",
+        "type": "github"
+      },
+      "original": {
+        "owner": "m-labs",
+        "repo": "migen",
+        "type": "github"
+      }
+    },
+    "src-misoc": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1649324486,
+        "narHash": "sha256-Mw/fQS3lHFvCm7L1k63joRkz5uyijQfywcOq+X2+o2s=",
+        "ref": "master",
+        "rev": "f1dc58d2b8c222ba41c25cee4301626625f46e43",
+        "revCount": 2420,
+        "submodules": true,
+        "type": "git",
+        "url": "https://github.com/m-labs/misoc.git"
+      },
+      "original": {
+        "submodules": true,
+        "type": "git",
+        "url": "https://github.com/m-labs/misoc.git"
+      }
+    },
+    "src-pythonparser": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1628745371,
+        "narHash": "sha256-p6TgeeaK4NEmbhimEXp31W8hVRo4DgWmcCoqZ+UdN60=",
+        "owner": "m-labs",
+        "repo": "pythonparser",
+        "rev": "5413ee5c9f8760e95c6acd5d6e88dabb831ad201",
+        "type": "github"
+      },
+      "original": {
+        "owner": "m-labs",
+        "repo": "pythonparser",
+        "type": "github"
+      }
+    },
+    "zynq-rs": {
+      "inputs": {
+        "mozilla-overlay": "mozilla-overlay_3",
+        "nixpkgs": [
+          "artiq-zynq",
+          "artiq",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1661505762,
+        "narHash": "sha256-gXML1pez4LvYxuAG9AX3inKq0e7+D8SvNd/tW4OwXu4=",
+        "ref": "master",
+        "rev": "92b3f3e1dd14fb2e53868665d95bbea4270da33e",
+        "revCount": 621,
+        "type": "git",
+        "url": "https://git.m-labs.hk/m-labs/zynq-rs"
+      },
+      "original": {
+        "type": "git",
+        "url": "https://git.m-labs.hk/m-labs/zynq-rs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000..c8e5e07
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,118 @@
+{
+  description = "Minimalist bare metal Rust firmware for Red Pitaya";
+
+  inputs.artiq-zynq.url = git+https://git.m-labs.hk/m-labs/artiq-zynq;
+
+  outputs = { self, artiq-zynq }:
+    let
+      pkgs = import artiq-zynq.inputs.artiq.inputs.nixpkgs { system = "x86_64-linux"; overlays = [ (import artiq-zynq.inputs.mozilla-overlay) ]; };
+      zynqpkgs = artiq-zynq.inputs.zynq-rs.packages.x86_64-linux;
+      artiqpkgs = artiq-zynq.inputs.artiq.packages.x86_64-linux;
+      artiqzynqpkgs = artiq-zynq.packages.x86_64-linux;
+      rustPlatform = artiq-zynq.inputs.zynq-rs.rustPlatform;
+    in {
+      packages.x86_64-linux = rec {
+      	rust-pitaya-firmware = rustPlatform.buildRustPackage {
+          name = "rust-pitaya-firmware";
+
+          src = ./src;
+          cargoLock = { 
+            lockFile = src/Cargo.lock;
+            outputHashes = {
+              "libasync-0.0.0" = "sha256-gXML1pez4LvYxuAG9AX3inKq0e7+D8SvNd/tW4OwXu4=";
+            };
+          };
+
+          nativeBuildInputs = [
+            pkgs.gnumake
+            (pkgs.python3.withPackages(ps: [ artiqpkgs.migen artiqzynqpkgs.migen-axi artiqpkgs.misoc ]))
+            pkgs.cargo-xbuild
+            pkgs.llvmPackages_9.llvm
+            pkgs.llvmPackages_9.clang-unwrapped
+          ];
+          buildPhase = ''
+            XARGO_RUST_SRC="${rustPlatform.rust.rustc}/lib/rustlib/src/rust/library";
+            export CARGO_HOME=$(mktemp -d cargo-home.XXX)
+            make
+          '';
+
+          installPhase = ''
+            mkdir -p $out $out/nix-support
+            cp ../build/firmware.bin $out/firmware.bin
+            cp ../build/firmware/armv7-none-eabihf/release/firmware $out/firmware.elf
+            echo file binary-dist $out/firmware.bin >> $out/nix-support/hydra-build-products
+            echo file binary-dist $out/firmware.elf >> $out/nix-support/hydra-build-products
+          '';
+
+          doCheck = false;
+          dontFixup = true;
+        };
+        rust-pitaya-gateware = pkgs.runCommand "rust-pitaya-gateware"
+          {
+            nativeBuildInputs = [ 
+              (pkgs.python3.withPackages(ps: [ artiqpkgs.migen artiqzynqpkgs.migen-axi artiqpkgs.misoc ]))
+              artiqpkgs.vivado
+            ];
+          }
+          ''
+          python ${./src/gateware}/rust-pitaya.py -g build
+          mkdir -p $out $out/nix-support
+          cp build/top.bit $out
+          echo file binary-dist $out/top.bit >> $out/nix-support/hydra-build-products
+          '';
+        rust-pitaya-jtag = pkgs.runCommand "rust-pitaya-jtag" {}
+          ''
+          mkdir $out
+          ln -s ${zynqpkgs.szl}/szl-redpitaya.elf $out
+          ln -s ${rust-pitaya-firmware}/firmware.bin $out
+          ln -s ${rust-pitaya-gateware}/top.bit $out
+          '';
+        rust-pitaya-sd = pkgs.runCommand "rust-pitaya-sd"
+          {
+            buildInputs = [ zynqpkgs.mkbootimage ];
+          }
+          ''
+          # Do not use "long" paths in boot.bif, because embedded developers
+          # can't write software (mkbootimage will segfault).
+          bifdir=`mktemp -d`
+          cd $bifdir
+          ln -s ${zynqpkgs.szl}/szl-redpitaya.elf szl.elf
+          ln -s ${rust-pitaya-firmware}/firmware.elf firmware.elf
+          ln -s ${rust-pitaya-gateware}/top.bit top.bit
+          cat > boot.bif << EOF
+          the_ROM_image:
+          {
+            [bootloader]szl.elf
+            top.bit
+            firmware.elf
+          }
+          EOF
+          mkdir $out $out/nix-support
+          mkbootimage boot.bif $out/boot.bin
+          echo file binary-dist $out/boot.bin >> $out/nix-support/hydra-build-products
+          '';
+      };
+      devShell.x86_64-linux = pkgs.mkShell {
+        name = "rust-pitaya-dev-shell";
+        buildInputs = with pkgs; [
+          pkgs.gnumake
+          rustPlatform.rust.rustc
+          rustPlatform.rust.cargo
+          pkgs.llvmPackages_9.llvm
+          pkgs.llvmPackages_9.clang-unwrapped
+          pkgs.cacert
+          cargo-xbuild
+
+          pkgs.openocd
+          pkgs.openssh pkgs.rsync
+          (pkgs.python3.withPackages(ps: [ artiqpkgs.migen artiqzynqpkgs.migen-axi artiqpkgs.misoc artiqzynqpkgs.artiq-netboot ]))
+          artiqpkgs.vivado
+
+          zynqpkgs.mkbootimage
+        ];
+        XARGO_RUST_SRC = "${rustPlatform.rust.rustc}/lib/rustlib/src/rust/library";
+        OPENOCD_ZYNQ = "${artiq-zynq.inputs.zynq-rs}/openocd";
+        SZL = "${zynqpkgs.szl}";
+      };
+    };
+}
diff --git a/local_run.sh b/local_run.sh
index e836f34..1188764 100755
--- a/local_run.sh
+++ b/local_run.sh
@@ -33,7 +33,7 @@ load_bitstream_cmd=""
 build_dir=`pwd`/build
 result_dir=`pwd`/result
 cd $OPENOCD_ZYNQ
-openocd -f redpitaya.cfg -c "load_image $SZL; resume 0; exit"
+openocd -f redpitaya.cfg -c "load_image $SZL/szl-redpitaya.elf; resume 0; exit"
 sleep 5
 if [ $impure -eq 1 ]; then
     if [ $load_bitstream -eq 1 ]; then
diff --git a/remote_run.sh b/remote_run.sh
index 3cfcff5..9de351c 100755
--- a/remote_run.sh
+++ b/remote_run.sh
@@ -46,7 +46,7 @@ echo "Creating $target_folder..."
 ssh $sshopts $target_host "mkdir -p $target_folder"
 echo "Copying files..."
 rsync -e "ssh $sshopts" -Lc $OPENOCD_ZYNQ/* $target_host:$target_folder
-rsync -e "ssh $sshopts" -Lc $SZL $target_host:$target_folder
+rsync -e "ssh $sshopts" -Lc $SZL/szl-redpitaya.elf $target_host:$target_folder
 if [ $impure -eq 1 ]; then
     if [ $load_bitstream -eq 1 ]; then
         load_bitstream_cmd="-g build/gateware/top.bit"
@@ -59,6 +59,6 @@ else
     firmware="$pure_dir/firmware.bin"
 fi
 echo "Programming board..."
-ssh $sshopts $target_host "cd $target_folder; openocd -f redpitaya.cfg -c'load_image szl.elf; resume 0; exit'"
+ssh $sshopts $target_host "cd $target_folder; openocd -f redpitaya.cfg -c'load_image szl-redpitaya.elf; resume 0; exit'"
 sleep 5
 artiq_netboot $load_bitstream_cmd -f $firmware -b $board_host
diff --git a/shell.nix b/shell.nix
deleted file mode 100644
index 5ce31c9..0000000
--- a/shell.nix
+++ /dev/null
@@ -1,33 +0,0 @@
-let
-  zynq-rs = (import ./zynq-rs.nix);
-  pkgs = import <nixpkgs> { overlays = [ (import "${zynq-rs}/nix/mozilla-overlay.nix") ]; };
-  rustPlatform = (import "${zynq-rs}/nix/rust-platform.nix" { inherit pkgs; });
-  cargo-xbuild = (import zynq-rs).cargo-xbuild;
-  artiq-fast = <artiq-fast>;
-  artiqpkgs = import "${artiq-fast}/default.nix" { inherit pkgs; };
-  vivado = import "${artiq-fast}/vivado.nix" { inherit pkgs; };
-  redpitaya-szl = (import zynq-rs).redpitaya-szl;
-in
-  pkgs.stdenv.mkDerivation {
-    name = "rust-pitaya-env";
-    buildInputs = [
-      pkgs.gnumake
-      rustPlatform.rust.rustc
-      rustPlatform.rust.cargo
-      pkgs.llvmPackages_9.llvm
-      pkgs.cacert
-      cargo-xbuild
-
-      pkgs.openocd
-      pkgs.openssh pkgs.rsync
-
-      (pkgs.python3.withPackages(ps: (with artiqpkgs; [ migen migen-axi misoc artiq-netboot ])))
-      vivado
-
-      (import "${zynq-rs}/nix/mkbootimage.nix" { inherit pkgs; })
-    ];
-
-    XARGO_RUST_SRC = "${rustPlatform.rust.rustc.src}/library";
-    OPENOCD_ZYNQ = "${zynq-rs}/openocd";
-    SZL = "${redpitaya-szl}/szl.elf";
-  }