diff --git a/src/CardinalLoader/Makefile b/src/CardinalLoader/Makefile
index ec9c1bb..ea4ae8e 100644
--- a/src/CardinalLoader/Makefile
+++ b/src/CardinalLoader/Makefile
@@ -8,10 +8,10 @@ NAME = CardinalLoader
 CARDINAL_VARIANT = loader
 include ../Makefile.cardinal.mk
 
-#ifndef CARDINAL_LOADER_IO
-#define CARDINAL_LOADER_IO 2
-#endif
+ifneq ($(CARDINAL_LOADER_IO),)
+BUILD_CXX_FLAGS += -DCARDINAL_LOADER_IO=$(CARDINAL_LOADER_IO)
+endif
 
-#ifndef CARDINAL_LOADER_PARAMS
-#define CARDINAL_LOADER_PARAMS 24
-#endif
+ifneq ($(CARDINAL_LOADER_PARAMS),)
+BUILD_CXX_FLAGS += -DCARDINAL_LOADER_PARAMS=$(CARDINAL_LOADER_PARAMS)
+endif