diff --git a/artiq/conda-artiq-board.nix b/artiq/conda-artiq-board.nix
index e4c0079..4368860 100644
--- a/artiq/conda-artiq-board.nix
+++ b/artiq/conda-artiq-board.nix
@@ -43,7 +43,6 @@ let
   conda-artiq-board = import ./conda-build.nix { inherit pkgs; } {
     name = "conda-artiq-board-${target}-${variant}";
     src = fakeCondaSource;
-    recipe = "fake-conda";
   };
 in
   conda-artiq-board
diff --git a/artiq/conda-artiq.nix b/artiq/conda-artiq.nix
index b419376..9e523b4 100644
--- a/artiq/conda-artiq.nix
+++ b/artiq/conda-artiq.nix
@@ -64,7 +64,6 @@ let
   conda-artiq = import ./conda-build.nix { inherit pkgs; } {
     name = "conda-artiq";
     src = fakeCondaSource;
-    recipe = "fake-conda";
   };
 in
   conda-artiq
diff --git a/artiq/conda-build.nix b/artiq/conda-build.nix
index 4116f5f..4ed0754 100644
--- a/artiq/conda-build.nix
+++ b/artiq/conda-build.nix
@@ -2,7 +2,7 @@
 # recipe must be a string pointing to a path within the source.
 
 { pkgs }:
-{ name, src, recipe }:
+{ name, src, recipe ? "fake-conda"}:
 
 with pkgs;