diff --git a/Makefile b/Makefile
index 01399bf..a934e1a 100644
--- a/Makefile
+++ b/Makefile
@@ -19,3 +19,4 @@ clean:
 
 %.SYS: %.o
 	$(CC65)/ld65 $(CCFLAGS) -o $@ $<
+	xattr -wx prodos.AuxType '00 20' $@