diff --git a/inc/fdb_low_lvl.h b/inc/fdb_low_lvl.h
index d7f287e..0f16047 100644
--- a/inc/fdb_low_lvl.h
+++ b/inc/fdb_low_lvl.h
@@ -21,6 +21,11 @@
 #define FDB_STATUS_TABLE_SIZE(status_number)       (((status_number - 1) * FDB_WRITE_GRAN + 7)/8)
 #endif
 
+/* the data is erased */
+#define FDB_BYTE_ERASED                           0xFF
+/* the data is written */
+#define FDB_BYTE_WRITTEN                          0x00
+
 /* Return the most contiguous size aligned at specified width. RT_ALIGN(13, 4)
  * would return 16.
  */
@@ -39,7 +44,11 @@
 #define FDB_DIRTY_STATUS_TABLE_SIZE               FDB_STATUS_TABLE_SIZE(FDB_SECTOR_DIRTY_STATUS_NUM)
 
 /* the data is unused */
-#define FDB_DATA_UNUSED                           0xFFFFFFFF
+#if (FDB_BYTE_ERASED  == 0xFF)
+#define FDB_DATA_UNUSED                      0xFFFFFFFF
+#else
+#define FDB_DATA_UNUSED                      0x00000000
+#endif
 
 fdb_err_t _fdb_kv_load(fdb_kvdb_t db);
 size_t _fdb_set_status(uint8_t status_table[], size_t status_num, size_t status_index);
diff --git a/src/fdb_kvdb.c b/src/fdb_kvdb.c
index dbd1c44..dea370a 100644
--- a/src/fdb_kvdb.c
+++ b/src/fdb_kvdb.c
@@ -56,7 +56,11 @@
 #endif
 
 /* the sector is not combined value */
+#if (FDB_BYTE_ERASED  == 0xFF)
 #define SECTOR_NOT_COMBINED                      0xFFFFFFFF
+#else
+#define SECTOR_NOT_COMBINED                      0x00000000
+#endif
 /* the next address is get failed */
 #define FAILED_ADDR                              0xFFFFFFFF
 
@@ -721,12 +725,12 @@ static fdb_err_t format_sector(fdb_kvdb_t db, uint32_t addr, uint32_t combined_v
     result = _fdb_flash_erase((fdb_db_t)db, addr, db_sec_size(db));
     if (result == FDB_NO_ERR) {
         /* initialize the header data */
-        memset(&sec_hdr, 0xFF, SECTOR_HDR_DATA_SIZE);
+        memset(&sec_hdr, FDB_BYTE_ERASED, SECTOR_HDR_DATA_SIZE);
         _fdb_set_status(sec_hdr.status_table.store, FDB_SECTOR_STORE_STATUS_NUM, FDB_SECTOR_STORE_EMPTY);
         _fdb_set_status(sec_hdr.status_table.dirty, FDB_SECTOR_DIRTY_STATUS_NUM, FDB_SECTOR_DIRTY_FALSE);
         sec_hdr.magic = SECTOR_MAGIC_WORD;
         sec_hdr.combined = combined_value;
-        sec_hdr.reserved = 0xFFFFFFFF;
+        sec_hdr.reserved = FDB_DATA_UNUSED;
         /* save the header */
         result = _fdb_flash_write((fdb_db_t)db, addr, (uint32_t *)&sec_hdr, SECTOR_HDR_DATA_SIZE, true);
 
@@ -1070,7 +1074,7 @@ static fdb_err_t align_write(fdb_kvdb_t db, uint32_t addr, const uint32_t *buf,
     size_t align_data_size = 1;
 #endif
 
-    memset(align_data, 0xFF, align_data_size);
+    memset(align_data, FDB_BYTE_ERASED, align_data_size);
     result = _fdb_flash_write((fdb_db_t)db, addr, buf, FDB_WG_ALIGN_DOWN(size), false);
 
     align_remain = size - FDB_WG_ALIGN_DOWN(size);
@@ -1094,7 +1098,7 @@ static fdb_err_t create_kv_blob(fdb_kvdb_t db, kv_sec_info_t sector, const char
         return FDB_KV_NAME_ERR;
     }
 
-    memset(&kv_hdr, 0xFF, KV_HDR_DATA_SIZE);
+    memset(&kv_hdr, FDB_BYTE_ERASED, KV_HDR_DATA_SIZE);
     kv_hdr.magic = KV_MAGIC_WORD;
     kv_hdr.name_len = strlen(key);
     kv_hdr.value_len = len;
@@ -1112,7 +1116,7 @@ static fdb_err_t create_kv_blob(fdb_kvdb_t db, kv_sec_info_t sector, const char
             result = update_sec_status(db, sector, kv_hdr.len, &is_full);
         }
         if (result == FDB_NO_ERR) {
-            uint8_t ff = 0xFF;
+            uint8_t ff = FDB_BYTE_ERASED;
             /* start calculate CRC32 */
             kv_hdr.crc32 = fdb_calc_crc32(0, &kv_hdr.name_len, KV_HDR_DATA_SIZE - KV_NAME_LEN_OFFSET);
             kv_hdr.crc32 = fdb_calc_crc32(kv_hdr.crc32, key, kv_hdr.name_len);
diff --git a/src/fdb_utils.c b/src/fdb_utils.c
index f80698e..044f35b 100644
--- a/src/fdb_utils.c
+++ b/src/fdb_utils.c
@@ -98,14 +98,18 @@ size_t _fdb_set_status(uint8_t status_table[], size_t status_num, size_t status_
      * |    8bit    | 0xFFFF              | 0x00FF              |  0x0000              |
      * |   32bit    | 0xFFFFFFFF FFFFFFFF | 0x00FFFFFF FFFFFFFF |  0x00FFFFFF 00FFFFFF |
      */
-    memset(status_table, 0xFF, FDB_STATUS_TABLE_SIZE(status_num));
+    memset(status_table, FDB_BYTE_ERASED, FDB_STATUS_TABLE_SIZE(status_num));
     if (status_index > 0) {
 #if (FDB_WRITE_GRAN == 1)
         byte_index = (status_index - 1) / 8;
+#if (FDB_BYTE_ERASED == 0xFF)
         status_table[byte_index] &= (0x00ff >> (status_index % 8));
+#else
+        status_table[byte_index] |= (0x00ff >> (status_index % 8));
+#endif
 #else
         byte_index = (status_index - 1) * (FDB_WRITE_GRAN / 8);
-        status_table[byte_index] = 0x00;
+        status_table[byte_index] = FDB_BYTE_WRITTEN;
 #endif /* FDB_WRITE_GRAN == 1 */
     }
 
@@ -123,7 +127,7 @@ size_t _fdb_get_status(uint8_t status_table[], size_t status_num)
             break;
         }
 #else /*  (FDB_WRITE_GRAN == 8) ||  (FDB_WRITE_GRAN == 32) ||  (FDB_WRITE_GRAN == 64) */
-        if (status_table[status_num * FDB_WRITE_GRAN / 8] == 0x00) {
+        if (status_table[status_num * FDB_WRITE_GRAN / 8] == FDB_BYTE_WRITTEN) {
             break;
         }
 #endif /* FDB_WRITE_GRAN == 1 */
@@ -173,7 +177,7 @@ size_t _fdb_read_status(fdb_db_t db, uint32_t addr, uint8_t status_table[], size
  */
 uint32_t _fdb_continue_ff_addr(fdb_db_t db, uint32_t start, uint32_t end)
 {
-    uint8_t buf[32], last_data = 0x00;
+    uint8_t buf[32], last_data = FDB_BYTE_WRITTEN;
     size_t i, addr = start, read_size;
 
     for (; start < end; start += sizeof(buf)) {
@@ -184,14 +188,14 @@ uint32_t _fdb_continue_ff_addr(fdb_db_t db, uint32_t start, uint32_t end)
         }
         _fdb_flash_read(db, start, (uint32_t *) buf, read_size);
         for (i = 0; i < read_size; i++) {
-            if (last_data != 0xFF && buf[i] == 0xFF) {
+            if (last_data != FDB_BYTE_ERASED && buf[i] == FDB_BYTE_ERASED) {
                 addr = start + i;
             }
             last_data = buf[i];
         }
     }
 
-    if (last_data == 0xFF) {
+    if (last_data == FDB_BYTE_ERASED) {
         return FDB_WG_ALIGN(addr);
     } else {
         return end;