diff --git a/docs/PORTING.md b/docs/PORTING.md
index 6bf09191..7210e571 100644
--- a/docs/PORTING.md
+++ b/docs/PORTING.md
@@ -119,11 +119,6 @@ int     flash_area_erase(const struct flash_area *, uint32_t off, uint32_t len);
 uint8_t flash_area_align(const struct flash_area *);
 /*< What is value is read from erased flash bytes. */
 uint8_t flash_area_erased_val(const struct flash_area *);
-/*< Reads len bytes from off, and checks if the read data is erased. Returns
-    1 if empty (that is containing erased value), 0 if not-empty, and -1 on
-    failure. */
-int     flash_area_read_is_empty(const struct flash_area *fa, uint32_t off,
-                     void *dst, uint32_t len);
 /*< Given flash area ID, return info about sectors within the area. */
 int     flash_area_get_sectors(int fa_id, uint32_t *count,
                      struct flash_sector *sectors);