diff --git a/atmel-samd/mpconfigport.h b/atmel-samd/mpconfigport.h
index 20c2c5f4d9..0e4e0bcf27 100644
--- a/atmel-samd/mpconfigport.h
+++ b/atmel-samd/mpconfigport.h
@@ -128,8 +128,10 @@ extern const struct _mp_obj_module_t uheap_module;
     { MP_OBJ_NEW_QSTR(MP_QSTR_board), (mp_obj_t)&board_module }, \
     { MP_OBJ_NEW_QSTR(MP_QSTR_uos), (mp_obj_t)&uos_module }, \
     { MP_OBJ_NEW_QSTR(MP_QSTR_time), (mp_obj_t)&time_module }, \
-    { MP_OBJ_NEW_QSTR(MP_QSTR_neopixel_write),(mp_obj_t)&neopixel_write_module }, \
-    { MP_OBJ_NEW_QSTR(MP_QSTR_uheap),(mp_obj_t)&uheap_module } \
+    { MP_OBJ_NEW_QSTR(MP_QSTR_neopixel_write),(mp_obj_t)&neopixel_write_module }
+
+#define MICROPY_PORT_BUILTIN_DEBUG_MODULES \
+    { MP_OBJ_NEW_QSTR(MP_QSTR_uheap),(mp_obj_t)&uheap_module }
 
 // board specific definitions
 #include "mpconfigboard.h"
diff --git a/py/objmodule.c b/py/objmodule.c
index 7ed3175c0d..48e373b844 100644
--- a/py/objmodule.c
+++ b/py/objmodule.c
@@ -219,6 +219,10 @@ STATIC const mp_rom_map_elem_t mp_builtin_module_table[] = {
 
     // extra builtin modules as defined by a port
     MICROPY_PORT_BUILTIN_MODULES
+
+#if defined(DEBUG) && defined(MICROPY_PORT_BUILTIN_DEBUG_MODULES)
+    , MICROPY_PORT_BUILTIN_DEBUG_MODULES
+#endif
 };
 
 STATIC MP_DEFINE_CONST_MAP(mp_builtin_module_map, mp_builtin_module_table);