diff --git a/artiq-full.nix b/artiq-full.nix
index 033d8df..6110dc5 100644
--- a/artiq-full.nix
+++ b/artiq-full.nix
@@ -62,7 +62,7 @@ let
     cp ${./artiq-full}/extras.nix $out
     cp ${./artiq-full}/*.patch $out
 
-    ${if a6p
+    ${if sinaraSystemsRev != null && sinaraSystemsHash != null
       then ''
         REV=${sinaraSystemsRev}
         HASH=${sinaraSystemsHash}
diff --git a/flake.nix b/flake.nix
index fd7388a..6b75b9b 100644
--- a/flake.nix
+++ b/flake.nix
@@ -24,13 +24,17 @@
     };
   };
 
-  outputs = sources@{ self, nixpkgs, ... }:
+  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};
@@ -71,10 +75,7 @@
           artiq-board-generated =
             (import ./artiq-board-generated {
               inherit pkgs;
-              sinaraSystemsSrc = null;
-              sinaraSystemsRev = sources.sinara-systems.rev;
-              sinaraSystemsHash = builtins.replaceStrings ["sha256-"] [""]
-                sources.sinara-systems.narHash;
+              inherit sinaraSystemsSrc sinaraSystemsRev sinaraSystemsHash;
               artiq-fast = artiq-fast-src;
             }).generated-nix;
 
@@ -82,7 +83,7 @@
             import ./artiq-full.nix {
               inherit pkgs a6p artiq-board-generated;
               artiq-fast = artiq-fast-src;
-              sinaraSystemsSrc = sources.sinara-systems.outPath;
+              inherit sinaraSystemsSrc sinaraSystemsRev sinaraSystemsHash;
             };
         in {
           inherit artiq-fast artiq-full;