diff --git a/pkgs/by-name/co/cosmic-bg/package.nix b/pkgs/by-name/co/cosmic-bg/package.nix
index e6b7d37c2696..f0a81198f680 100644
--- a/pkgs/by-name/co/cosmic-bg/package.nix
+++ b/pkgs/by-name/co/cosmic-bg/package.nix
@@ -30,7 +30,7 @@ rustPlatform.buildRustPackage rec {
   };
 
   postPatch = ''
-    substituteInPlace justfile --replace '#!/usr/bin/env' "#!$(command -v env)"
+    substituteInPlace justfile --replace-fail '#!/usr/bin/env' "#!$(command -v env)"
   '';
 
   nativeBuildInputs = [ just pkg-config makeBinaryWrapper ];