diff --git a/include/lv_conf_v7.h b/include/lv_conf_v7.h
index e2adf67e..764be7bd 100644
--- a/include/lv_conf_v7.h
+++ b/include/lv_conf_v7.h
@@ -80,8 +80,10 @@ typedef int16_t lv_coord_t;
 #define LV_FS_SEEK(x, y) lv_fs_seek(x, y)
 #define _lv_img_decoder_t _lv_img_decoder
 
+#ifndef LV_MEM_CUSTOM
   /* 1: use custom malloc/free, 0: use the built-in `lv_mem_alloc` and `lv_mem_free` */
 #define LV_MEM_CUSTOM      0
+#endif
 #if LV_MEM_CUSTOM == 0
 /* Size of the memory used by `lv_mem_alloc` in bytes (>= 2kB)*/