diff --git a/pkgs/applications/misc/phwmon/default.nix b/pkgs/applications/misc/phwmon/default.nix
index 22d94006ddc..719c3dc9998 100644
--- a/pkgs/applications/misc/phwmon/default.nix
+++ b/pkgs/applications/misc/phwmon/default.nix
@@ -17,7 +17,7 @@ stdenv.mkDerivation {
 
   pythonPath = [ python2Packages.pygtk python2Packages.psutil ];
 
-  patchPhase = ''
+  postPatch = ''
     substituteInPlace install.sh --replace "/usr/local" "$out"
   '';