diff --git a/libraries/AP_HAL/board/empty.h b/libraries/AP_HAL/board/empty.h
index b2843afa7c..deb88a341f 100644
--- a/libraries/AP_HAL/board/empty.h
+++ b/libraries/AP_HAL/board/empty.h
@@ -3,7 +3,9 @@
 #define HAL_BOARD_NAME "EMPTY"
 #define HAL_CPU_CLASS HAL_CPU_CLASS_150
 #define HAL_MEM_CLASS HAL_MEM_CLASS_192
+#ifndef HAL_STORAGE_SIZE
 #define HAL_STORAGE_SIZE            16384
+#endif
 #define HAL_STORAGE_SIZE_AVAILABLE  HAL_STORAGE_SIZE
 #define HAL_INS_DEFAULT HAL_INS_NONE
 #define HAL_BARO_DEFAULT HAL_BARO_NONE