diff --git a/pkgs/servers/klipper/default.nix b/pkgs/servers/klipper/default.nix
index d44395613d4c..08f30b654b0c 100644
--- a/pkgs/servers/klipper/default.nix
+++ b/pkgs/servers/klipper/default.nix
@@ -77,12 +77,12 @@ stdenv.mkDerivation rec {
   postPatch = ''
     for file in klippy.py console.py parsedump.py; do
       substituteInPlace $file \
-        --replace '/usr/bin/env python2' '/usr/bin/env python'
+        --replace-warn '/usr/bin/env python2' '/usr/bin/env python'
     done
 
     # needed for cross compilation
     substituteInPlace ./chelper/__init__*.py \
-      --replace 'GCC_CMD = "gcc"' 'GCC_CMD = "${stdenv.cc.targetPrefix}cc"'
+      --replace-warn 'GCC_CMD = "gcc"' 'GCC_CMD = "${stdenv.cc.targetPrefix}cc"'
   '';
 
   pythonInterpreter =