diff --git a/packages/linuxcnc-ethercat/default.nix b/packages/linuxcnc-ethercat/default.nix
index cbfeb63..5208f5a 100644
--- a/packages/linuxcnc-ethercat/default.nix
+++ b/packages/linuxcnc-ethercat/default.nix
@@ -17,7 +17,12 @@ stdenv.mkDerivation rec {
 
   buildInputs = [ linuxcnc ethercat ];
 
-  installFlags = [ "DESTDIR=${placeholder "out"}" ];
+  installFlags = [
+    "DESTDIR=${placeholder "out"}"
+    "EMC2_HOME=''"
+    "LIBDIR=''"
+    "RTLIBDIR='/lib/linuxcnc/modules'"
+  ];
 
   meta = with lib; {
     description = "LinuxCNC ethercat interop";