diff --git a/pkgs/by-name/ku/kubectl/package.nix b/pkgs/by-name/ku/kubectl/package.nix
index b446f21cfdd5..a4a76bc4b211 100644
--- a/pkgs/by-name/ku/kubectl/package.nix
+++ b/pkgs/by-name/ku/kubectl/package.nix
@@ -9,7 +9,7 @@ kubernetes.overrideAttrs (_: {
     "convert"
   ];
 
-  WHAT = lib.concatStringsSep " " [
+  env.WHAT = toString [
     "cmd/kubectl"
     "cmd/kubectl-convert"
   ];
diff --git a/pkgs/by-name/ku/kubernetes/package.nix b/pkgs/by-name/ku/kubernetes/package.nix
index 4f3451cbab3d..adcb906fcac5 100644
--- a/pkgs/by-name/ku/kubernetes/package.nix
+++ b/pkgs/by-name/ku/kubernetes/package.nix
@@ -51,7 +51,7 @@ buildGoModule (finalAttrs: {
 
   patches = [ ./fixup-addonmanager-lib-path.patch ];
 
-  WHAT = lib.concatStringsSep " " components;
+  env.WHAT = toString components;
 
   buildPhase = ''
     runHook preBuild