diff --git a/inc/fdb_cfg_template.h b/inc/fdb_cfg_template.h
index f8bde78..ee96d92 100644
--- a/inc/fdb_cfg_template.h
+++ b/inc/fdb_cfg_template.h
@@ -34,7 +34,7 @@
 
 #ifdef FDB_USING_FAL_MODE
 /* the flash write granularity, unit: bit
- * only support 1(nor flash)/ 8(stm32f2/f4)/ 32(stm32f1)/ 64(stm32f7)/ 128(stm32h5) */
+ * only support 1(nor flash)/ 8(stm32f2/f4)/ 32(stm32f1)/ 64(stm32f7)/ 128(stm32h5)/ 256(stm32h7) */
 #define FDB_WRITE_GRAN                /* @note you must define it for a value */
 #endif
 
diff --git a/src/fdb_kvdb.c b/src/fdb_kvdb.c
index 10c29d4..9438324 100644
--- a/src/fdb_kvdb.c
+++ b/src/fdb_kvdb.c
@@ -27,8 +27,8 @@
 #error "Please configure flash write granularity (in fdb_cfg.h)"
 #endif
 
-#if FDB_WRITE_GRAN != 1 && FDB_WRITE_GRAN != 8 && FDB_WRITE_GRAN != 32 && FDB_WRITE_GRAN != 64 && FDB_WRITE_GRAN != 128
-#error "the write gran can be only setting as 1, 8, 32, 64 and 128"
+#if FDB_WRITE_GRAN != 1 && FDB_WRITE_GRAN != 8 && FDB_WRITE_GRAN != 32 && FDB_WRITE_GRAN != 64 && FDB_WRITE_GRAN != 128 && FDB_WRITE_GRAN != 256
+#error "the write gran can be only setting as 1, 8, 32, 64, 128 and 256"
 #endif
 
 /* magic word(`F`, `D`, `B`, `1`) */
@@ -109,6 +109,8 @@ struct sector_hdr_data {
     uint32_t reserved;
 #if (FDB_WRITE_GRAN == 64) || (FDB_WRITE_GRAN == 128)
     uint8_t padding[4];                          /**< align padding for 64bit and 128bit write granularity */
+#elif (FDB_WRITE_GRAN == 256)
+    uint8_t padding[20];                         /**< align padding for 256bit write granularity */
 #endif
 };
 typedef struct sector_hdr_data *sector_hdr_data_t;
@@ -122,9 +124,10 @@ struct kv_hdr_data {
     uint32_t value_len;                          /**< value length */
 #if (FDB_WRITE_GRAN == 64)
     uint8_t padding[4];                          /**< align padding for 64bit write granularity */
-#endif
-#if (FDB_WRITE_GRAN == 128)
-    uint8_t padding[12];                         /**< align padding for 128bit write granularity */
+#elif (FDB_WRITE_GRAN == 128)
+    uint8_t padding[12];                          /**< align padding for 128bit write granularity */
+#elif (FDB_WRITE_GRAN == 256)
+    uint8_t padding[15];                          /**< align padding for 256bit write granularity */
 #endif
 };
 typedef struct kv_hdr_data *kv_hdr_data_t;
diff --git a/src/fdb_tsdb.c b/src/fdb_tsdb.c
index bc53375..c023a00 100644
--- a/src/fdb_tsdb.c
+++ b/src/fdb_tsdb.c
@@ -25,8 +25,8 @@
 
 #if defined(FDB_USING_TSDB)
 
-#if (FDB_WRITE_GRAN == 64) || (FDB_WRITE_GRAN == 128)
-#error "Flash 64 or 128 bits write granularity is not supported in TSDB yet!"
+#if (FDB_WRITE_GRAN == 64) || (FDB_WRITE_GRAN == 128) || (FDB_WRITE_GRAN == 256)
+#error "Flash 64 or 128 or 256 bits write granularity is not supported in TSDB yet!"
 #endif
 
 /* magic word(`T`, `S`, `L`, `0`) */