diff --git a/boot/init/default.nix b/boot/init/default.nix
index a4a43f27..428ea04a 100644
--- a/boot/init/default.nix
+++ b/boot/init/default.nix
@@ -51,6 +51,7 @@ stdenv.mkDerivation {
 
     # This is the "script" that will be loaded.
     mrbc \
+      ${lib.optionalString mruby.debug "-g"} \
       -o init.mrb \
       ${libs} \
       $(find lib -type f | sort) \