diff --git a/pkgs/os-specific/linux/kernel/manual-config.nix b/pkgs/os-specific/linux/kernel/manual-config.nix
index 12eca63e2162..53e04b684d6d 100644
--- a/pkgs/os-specific/linux/kernel/manual-config.nix
+++ b/pkgs/os-specific/linux/kernel/manual-config.nix
@@ -261,8 +261,7 @@ let
         find .  -type f -name '*.lds' -print0 | xargs -0 -r chmod u-w
 
         # Keep root and arch-specific Makefiles
-        chmod u-w Makefile
-        chmod u-w arch/$arch/Makefile*
+        chmod u-w Makefile arch/"$arch"/Makefile*
 
         # Keep whole scripts dir
         chmod u-w -R scripts