diff --git a/main.nix b/main.nix
index d0b4967..a32082a 100644
--- a/main.nix
+++ b/main.nix
@@ -1,5 +1,5 @@
-{ pkgs ? import <nixpkgs> {}}:
 let
+  pkgs = import <nixpkgs> {};
   artiqSrc = <artiqSrc>;
   generatedNix = pkgs.runCommand "generated-nix" { buildInputs = [ pkgs.nix pkgs.git ]; }
     ''
@@ -34,6 +34,8 @@ let
     # This is in the example in the ARTIQ manual - precompile it to speed up
     # installation for users.
     matplotlib-qt = pkgs.lib.hydraJob (pkgs.python3Packages.matplotlib.override { enableQt = true; });
+    # For Raspberry Pi JTAG servers
+    openocd-aarch64 = pkgs.lib.hydraJob ((import <nixpkgs> { system = "aarch64-linux"; }).callPackage ./artiq/pkgs/openocd.nix {});
   };
 in
   jobs // {
diff --git a/nixbld-etc-nixos/configuration.nix b/nixbld-etc-nixos/configuration.nix
index b3f0b22..019f193 100644
--- a/nixbld-etc-nixos/configuration.nix
+++ b/nixbld-etc-nixos/configuration.nix
@@ -68,6 +68,10 @@
     extraGroups = ["networkmanager" "wheel" "plugdev" "dialout" "lp" "scanner"];
     uid = 1000;
   };
+  users.extraUsers.nix = {
+    isNormalUser = true;
+    uid = 1001;
+  };
   security.sudo.wheelNeedsPassword = false;
   services.udev.packages = [ pkgs.openocd ];
   services.udev.extraRules = ''
@@ -89,6 +93,7 @@ ACTION=="add", SUBSYSTEM=="tty", \
 
   nixpkgs.config.allowUnfree = true;
 
+  nix.distributedBuilds = true;
   nix.buildMachines = [
     {
        hostName = "localhost";
@@ -96,6 +101,13 @@ ACTION=="add", SUBSYSTEM=="tty", \
        system = "x86_64-linux";
        supportedFeatures = ["big-parallel"];
     }
+    {
+       hostName = "rpi-1";
+       sshUser = "nix";
+       sshKey = "/home/nix/.ssh/id_rsa";
+       maxJobs = 1;
+       system = "aarch64-linux";
+    }
   ];
   services.hydra = {
     enable = true;
diff --git a/rpi-etc-nixos/configuration.nix b/rpi-etc-nixos/configuration.nix
index 5c141ef..d6f73b1 100644
--- a/rpi-etc-nixos/configuration.nix
+++ b/rpi-etc-nixos/configuration.nix
@@ -27,12 +27,16 @@ in
   time.timeZone = "Asia/Hong_Kong";
 
   users.extraGroups.plugdev = { };
+  security.sudo.wheelNeedsPassword = false;
   users.extraUsers.sb = {
     isNormalUser = true;
     extraGroups = ["wheel" "plugdev" "dialout"];
     uid = 1000;
   };
-  security.sudo.wheelNeedsPassword = false;
+  users.extraUsers.nix = {
+    isNormalUser = true;
+    uid = 1001;
+  };
   services.udev.packages = [ m-labs.openocd ];
 
   environment.systemPackages = with pkgs; [
@@ -41,4 +45,5 @@ in
 
   nix.binaryCachePublicKeys = ["nixbld.m-labs.hk-1:5aSRVA5b320xbNvu30tqxVPXpld73bhtOeH6uAjRyHc="];
   nix.binaryCaches = ["https://cache.nixos.org" "https://nixbld.m-labs.hk"];
+  nix.trustedUsers = ["root" "nix"];
 }