diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5ae6bcf..34e2c03 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -274,9 +274,11 @@ set(SOURCES
   src/fs/fygue/fygue_file_read.c
   src/fs/fygue/fat/cluster.c
   src/fs/fygue/fat/fat.c
+  src/fs/fygue/fat/fat_dir_open.c
   src/fs/fygue/fat/fat_dir_read.c
   src/fs/fygue/fat/fat_dir_close.c
   src/fs/fygue/fat/fat_dir_stat.c
+  src/fs/fygue/fat/fat_file_open.c
   src/fs/fygue/fat/fat_file_stat.c
   src/fs/fygue/fat/fat_file_close.c
   src/fs/fygue/fat/fat_file_read.c
diff --git a/src/fs/fygue/fat/fat.c b/src/fs/fygue/fat/fat.c
index 840eb07..30b2e72 100644
--- a/src/fs/fygue/fat/fat.c
+++ b/src/fs/fygue/fat/fat.c
@@ -153,8 +153,8 @@ static int _fygue_fat_prepare(struct fygue_fat *fat)
 // Public
 //---
 
-/* fygue_fat_init_cold() - fully initialize the FAT information */
-int fygue_fat_init_cold(struct fygue_fat *fat)
+/* fygue_fat_initialize() - fully initialize the FAT information */
+int fygue_fat_initialize(struct fygue_fat *fat)
 {
     if (fat == NULL)
         return -1;
@@ -170,11 +170,14 @@ int fygue_fat_init_cold(struct fygue_fat *fat)
     return 0;
 }
 
-/* fygue_fat_init_hot(): re-initialize the FAT information */
-int fygue_fat_init_hot(struct fygue_fat *fat)
+/* fygue_fat_sync(): re-initialize the FAT information */
+int fygue_fat_sync(struct fygue_fat *fat)
 {
-    //FIXME: implement
-    (void)fat;
-    errno = ENOTSUP;
-    return -3;
+    if (fat == NULL)
+        return -1;
+    if (fygue_flash_sync((&fat->_flash)) != 0)
+        return -2;
+    if (_fygue_fat_prepare(fat) != 0)
+        return -3;
+    return 0;
 }
diff --git a/src/fs/fygue/fat/fat.h b/src/fs/fygue/fat/fat.h
index b33dd11..4701440 100644
--- a/src/fs/fygue/fat/fat.h
+++ b/src/fs/fygue/fat/fat.h
@@ -82,11 +82,13 @@ struct fygue_fat_file
     int cluster_entry;
     int attribute;
     size_t size;
+    off_t cursor;
     struct {
         uintptr_t addr;
         size_t size;
         int cluster_count;
     } *chunk;
+    int chunk_table_max_index;
     int chunk_count;
     int chunk_rd_index;
     int chunk_rd_offset;
@@ -105,11 +107,11 @@ struct fygue_fat_resolve
     };
 };
 
-/* fygue_fat_init_cold() - fully initialize the FAT information */
-extern int fygue_fat_init_cold(struct fygue_fat *fat);
+/* fygue_fat_initialize() - fully initialize the FAT information */
+extern int fygue_fat_initialize(struct fygue_fat *fat);
 
-/* fygue_fat_init_hot() - re-initialize the FAT information */
-extern int fygue_fat_init_hot(struct fygue_fat *fat);
+/* fygue_fat_sync() - re-initialize the FAT information */
+extern int fygue_fat_sync(struct fygue_fat *fat);
 
 /* fygue_fat_resolve() - resolve the path and set the dirent information */
 extern int fygue_fat_resolve(
@@ -122,6 +124,13 @@ extern int fygue_fat_resolve(
 // Directory interface
 //---
 
+/* fugue_fat_dir_open(): convert dirent to dir */
+extern int fygue_fat_dir_open(
+    struct fygue_fat *fat,
+    struct fygue_fat_dir *dir,
+    struct fygue_fat_dirent *dirent
+);
+
 /* fygue_fat_dir_read(): readdir primitive */
 extern int fygue_fat_dir_read(
     struct fygue_fat *fat,
@@ -142,10 +151,23 @@ extern int fygue_fat_dir_stat(
     struct stat *statbuf
 );
 
+/* fygue_fat_dir_sync(): sync directory information */
+extern int fygue_fat_dir_sync(
+    struct fygue_fat *fat,
+    struct fygue_fat_dir *dir
+);
+
 //---
 // File interface
 //---
 
+/* _fygue_fat_file_open(): generate file information */
+extern int fygue_fat_file_open(
+    struct fygue_fat *fat,
+    struct fygue_fat_file *file,
+    struct fygue_fat_dirent *dirent
+);
+
 /* fygue_fat_file_read(): read primitive */
 extern int fygue_fat_file_read(
     struct fygue_fat *fat,
@@ -171,7 +193,13 @@ extern int fygue_fat_file_seek(
 /* fygue_fat_file_close(): close primitive */
 extern int fygue_fat_file_close(
     struct fygue_fat *fat,
-    struct fygue_fat_file *dir
+    struct fygue_fat_file *file
+);
+
+/* fygue_fat_file_sync(): sync internal information */
+extern int fygue_fat_file_sync(
+    struct fygue_fat *fat,
+    struct fygue_fat_file *file
 );
 
 //---
diff --git a/src/fs/fygue/fat/fat_dir_open.c b/src/fs/fygue/fat/fat_dir_open.c
new file mode 100644
index 0000000..0c43768
--- /dev/null
+++ b/src/fs/fygue/fat/fat_dir_open.c
@@ -0,0 +1,44 @@
+#include <string.h>
+#include "fat.h"
+
+/* fugue_fat_dir_open(): convert dirent to dir */
+int fygue_fat_dir_open(
+    struct fygue_fat *fat,
+    struct fygue_fat_dir *dir,
+    struct fygue_fat_dirent *dirent
+) {
+    int rc;
+
+    memset(dir, 0x00, sizeof(struct fygue_fat_dir));
+    if (dirent == NULL) {
+        dir->cluster_entry      = 0;
+        dir->root_dirent_count  = fat->RootEntCount;
+        dir->attribute          = FYGUE_FAT_FILE_TYPE_DIR;
+    } else {
+        if ((dirent->attribute & FYGUE_FAT_FILE_TYPE_DIR) == 0x00)
+            return -1;
+        dir->cluster_entry      = dirent->cluster_id;
+        dir->attribute          = FYGUE_FAT_FILE_TYPE_DIR;
+        dir->root_dirent_count  = 0;
+    }
+    dir->dirty           = false;
+    dir->sector_count    = 0;
+    dir->dirent_cursor   = 0;
+    dir->end_of_dirent   = false;
+    dir->cluster_current = dir->cluster_entry;
+    rc = fygue_fat_cluster_get_sector(
+        fat,
+        dir->cluster_current,
+        &dir->sector_id
+    );
+    if (rc != 0)
+        return -2;
+    rc = fygue_fat_sector_get_addr(
+        fat,
+        &dir->dirent_current_addr,
+        dir->sector_id
+    );
+    if (rc != 0)
+        return -3;
+    return 0;
+}
diff --git a/src/fs/fygue/fat/fat_dir_sync.c b/src/fs/fygue/fat/fat_dir_sync.c
new file mode 100644
index 0000000..8f2761a
--- /dev/null
+++ b/src/fs/fygue/fat/fat_dir_sync.c
@@ -0,0 +1,12 @@
+#include "fat.h"
+
+/* fygue_fat_dir_sync(): sync directory information */
+int fygue_fat_dir_sync(
+    struct fygue_fat *fat,
+    struct fygue_fat_dir *dir
+) {
+    if (fat == NULL || dir == NULL)
+        return -1;
+    // nothing to do (?)
+    return 0;
+}
diff --git a/src/fs/fygue/fat/fat_file_open.c b/src/fs/fygue/fat/fat_file_open.c
new file mode 100644
index 0000000..b0f4de7
--- /dev/null
+++ b/src/fs/fygue/fat/fat_file_open.c
@@ -0,0 +1,25 @@
+#include <string.h>
+#include <stdlib.h>
+#include "fat.h"
+
+/* fygue_fat_file_open(): generate file information */
+int fygue_fat_file_open(
+    struct fygue_fat *fat,
+    struct fygue_fat_file *file,
+    struct fygue_fat_dirent *dirent
+) {
+    memset(file, 0x00, sizeof(struct fygue_fat_file));
+    file->attribute             = dirent->attribute;
+    file->cluster_entry         = dirent->cluster_id;
+    file->size                  = dirent->size;
+    file->chunk                 = NULL;
+    file->chunk_count           = 0;
+    file->chunk_table_max_index = 0;
+    if (fygue_fat_file_sync(fat, file) != 0)
+        return -1;
+    if (fygue_fat_file_seek(fat, file, 0) != 0)
+        return -2;
+    return 0;
+}
+
+
diff --git a/src/fs/fygue/fat/fat_file_seek.c b/src/fs/fygue/fat/fat_file_seek.c
index 458ad64..c9b3c37 100644
--- a/src/fs/fygue/fat/fat_file_seek.c
+++ b/src/fs/fygue/fat/fat_file_seek.c
@@ -21,6 +21,7 @@ int fygue_fat_file_seek(
         offset_test += file->chunk[i].size;
         if (offset_test > offset) {
             file->chunk_rd_offset = offset - offset_test;
+            file->cursor = offset;
             return 0;
         }
         file->chunk_rd_index += 1;
diff --git a/src/fs/fygue/fat/fat_file_sync.c b/src/fs/fygue/fat/fat_file_sync.c
new file mode 100644
index 0000000..0adda80
--- /dev/null
+++ b/src/fs/fygue/fat/fat_file_sync.c
@@ -0,0 +1,84 @@
+#include <stdlib.h>
+#include "fat.h"
+
+//---
+// Internals
+//---
+
+/* _fygue_chunk_table_update(): update chunk table */
+static int _fygue_chunk_table_update(
+    struct fygue_fat_file *file,
+    uintptr_t cluster_addr
+) {
+    uintptr_t cluster_addr_prev;
+    void *tmp;
+
+    if (file->chunk_count > 0)
+    {
+        cluster_addr_prev  = file->chunk[file->chunk_count - 1].addr;
+        cluster_addr_prev += file->chunk[file->chunk_count - 1].size;
+        if (cluster_addr == cluster_addr_prev)
+        {
+            file->chunk[file->chunk_count - 1].size += 8*512;
+            file->chunk[file->chunk_count - 1].cluster_count += 1;
+            return 0;
+        }
+    }
+    if (file->chunk_count >= file->chunk_table_max_index)
+    {
+        tmp = reallocarray(
+            file->chunk,
+            file->chunk_table_max_index + 1,
+            sizeof(*file->chunk)
+        );
+        if (tmp == NULL)
+            return -1;
+        file->chunk = tmp;
+        file->chunk_table_max_index += 1;
+    }
+    file->chunk[file->chunk_count].size = 8*512;
+    file->chunk[file->chunk_count].addr = cluster_addr;
+    file->chunk[file->chunk_count].cluster_count = 1;
+    file->chunk_count += 1;
+    return 0;
+}
+
+/* _fygue_chunk_error(): invalidate the chunk table */
+static int _fygue_chunk_error(struct fygue_fat_file *file)
+{
+    if (file->chunk == NULL)
+        free(file->chunk);
+    file->chunk_table_max_index = 0;
+    file->chunk_count = 0;
+    return -1;
+}
+
+//---
+// Public
+//---
+
+/* fygue_fat_file_sync(): sync internal information */
+int fygue_fat_file_sync(
+    struct fygue_fat *fat,
+    struct fygue_fat_file *file
+) {
+    uintptr_t cluster_addr;
+    int cluster_id;
+
+    if (fat == NULL || file == NULL)
+        return -1;
+    file->chunk_count = 0;
+    cluster_id = file->cluster_entry;
+    while (true)
+    {
+        if (fygue_fat_cluster_get_addr(fat, &cluster_addr, cluster_id) != 0)
+            return _fygue_chunk_error(file);
+        if (_fygue_chunk_table_update(file, cluster_addr) != 0)
+            return _fygue_chunk_error(file);
+        if (fygue_fat_cluster_get_next(fat, &cluster_id) != 0)
+            break;
+    }
+    if (fygue_fat_file_seek(fat, file, file->cursor) != 0)
+        return -3;
+    return 0;
+}
diff --git a/src/fs/fygue/fat/resolve.c b/src/fs/fygue/fat/resolve.c
index 6400c0c..73f8bc2 100644
--- a/src/fs/fygue/fat/resolve.c
+++ b/src/fs/fygue/fat/resolve.c
@@ -31,108 +31,6 @@ static int _fygue_path_get_name(
     return 0;
 }
 
-/* _fygue_dirent_resolve_file(): generate file information
- *
- * notes
- *   - assume FAT integrity */
-static int _fygue_dirent_resolve_file(
-    struct fygue_fat *fat,
-    struct fygue_fat_file *file,
-    struct fygue_fat_dirent *dirent
-) {
-    uintptr_t cluster_addr_prev;
-    uintptr_t cluster_addr;
-    size_t cluster_size;
-    int cluster;
-    void *tmp;
-
-    memset(file, 0x00, sizeof(struct fygue_fat_file));
-    file->attribute     = dirent->attribute;
-    file->cluster_entry = dirent->cluster_id;
-    file->size          = dirent->size;
-    file->chunk         = NULL;
-    file->chunk_count   = 0;
-
-    cluster = file->cluster_entry;
-    cluster_size = fat->SectorSize * fat->SectorPerClus;
-    while (true)
-    {
-        if (fygue_fat_cluster_get_addr(fat, &cluster_addr, cluster) != 0)
-            goto error;
-        if (file->chunk_count > 0) {
-            cluster_addr_prev  = file->chunk[file->chunk_count - 1].addr;
-            cluster_addr_prev += file->chunk[file->chunk_count - 1].size;
-            if (cluster_addr == cluster_addr_prev) {
-                file->chunk[file->chunk_count - 1].size += cluster_size;
-                file->chunk[file->chunk_count - 1].cluster_count += 1;
-                if (fygue_fat_cluster_get_next(fat, &cluster) != 0)
-                    break;
-                continue;
-            }
-        }
-        tmp = reallocarray(
-            file->chunk,
-            file->chunk_count + 1,
-            sizeof(*file->chunk)
-        );
-        if (tmp == NULL)
-            goto error;
-        file->chunk = tmp;
-        file->chunk[file->chunk_count].size = cluster_size;
-        file->chunk[file->chunk_count].addr = cluster_addr;
-        file->chunk[file->chunk_count].cluster_count = 1;
-        file->chunk_count += 1;
-        if (fygue_fat_cluster_get_next(fat, &cluster) != 0)
-            break;
-    }
-    return 0;
-error:
-    if (file->chunk == NULL)
-        free(file->chunk);
-    memset(file, 0x00, sizeof(struct fygue_fat_file));
-    return -1;
-}
-
-/* _fugue_dirent_resolve_dir(): convert found dirent to dir */
-static int _fygue_dirent_resolve_dir(
-    struct fygue_fat *fat,
-    struct fygue_fat_dir *dir,
-    struct fygue_fat_dirent *dirent
-) {
-    int rc;
-
-    memset(dir, 0x00, sizeof(struct fygue_fat_dir));
-    if (dirent == NULL) {
-        dir->cluster_entry      = 0;
-        dir->root_dirent_count  = fat->RootEntCount;
-        dir->attribute          = FYGUE_FAT_FILE_TYPE_DIR;
-    } else {
-        if ((dirent->attribute & FYGUE_FAT_FILE_TYPE_DIR) == 0x00)
-            return -1;
-        dir->cluster_entry      = dirent->cluster_id;
-        dir->attribute          = FYGUE_FAT_FILE_TYPE_DIR;
-        dir->root_dirent_count  = 0;
-    }
-    dir->dirty           = false;
-    dir->sector_count    = 0;
-    dir->dirent_cursor   = 0;
-    dir->end_of_dirent   = false;
-    dir->cluster_current = dir->cluster_entry;
-    rc = fygue_fat_cluster_get_sector(
-        fat,
-        dir->cluster_current,
-        &dir->sector_id
-    );
-    if (rc != 0)
-        return -2;
-    rc = fygue_fat_sector_get_addr(
-        fat,
-        &dir->dirent_current_addr,
-        dir->sector_id
-    );
-    return (rc != 0) ? -3 : 0;
-}
-
 /* _fygue_opendir_find() - try to find the directory entry */
 static int _fygue_dirent_find(
     struct fygue_fat *fat,
@@ -159,10 +57,10 @@ static int _fygue_resolve_set(
 ) {
     if (dirent == NULL || (dirent->attribute & FYGUE_FAT_ATTR_DIRECTORY)) {
         resolve->type = FYGUE_FAT_FILE_TYPE_DIR;
-        return _fygue_dirent_resolve_dir(fat, &(resolve->dir), dirent);
+        return fygue_fat_dir_open(fat, &(resolve->dir), dirent);
     }
     resolve->type = FYGUE_FAT_FILE_TYPE_FILE;
-    return _fygue_dirent_resolve_file(fat, &(resolve->file), dirent);
+    return fygue_fat_file_open(fat, &(resolve->file), dirent);
 }
 
 //---
@@ -194,7 +92,7 @@ int fygue_fat_resolve(
     while (true)
     {
         if (is_root) {
-            if (_fygue_dirent_resolve_dir(fat, &dir, NULL) != 0)
+            if (fygue_fat_dir_open(fat, &dir, NULL) != 0)
                 return -3;
             if (_fygue_path_get_name(&prefix, &start, &len) != 0)
                 break;
@@ -205,7 +103,7 @@ int fygue_fat_resolve(
             return -4;
         if (_fygue_path_get_name(&prefix, &start, &len) != 0)
             break;
-        if (_fygue_dirent_resolve_dir(fat, &dir, &dirent) != 0)
+        if (fygue_fat_dir_open(fat, &dir, &dirent) != 0)
             return -5;
     }
     if (is_root)
diff --git a/src/fs/fygue/flash/cmap.c b/src/fs/fygue/flash/cmap.c
index b16d669..e61f0ca 100644
--- a/src/fs/fygue/flash/cmap.c
+++ b/src/fs/fygue/flash/cmap.c
@@ -78,6 +78,33 @@ static int fygue_flash_cmap_update(
 // Public
 //---
 
+/* fygue_flash_cmap_lsector_get_addr() - get logical sector address */
+int fygue_flash_cmap_lsector_get_addr(
+    struct fygue_flash *flash,
+    struct fygue_flash_cmap *cmap,
+    uintptr_t *sector,
+    uint16_t lsector_id
+) {
+    uintptr_t fsector_addr;
+    uint16_t lcluster_id;
+
+    if (flash == NULL  || sector == NULL || cmap == NULL)
+        return -1;
+    if (cmap->lcluster == NULL)
+        return -1;
+    lcluster_id = lsector_id / 8;
+    if (
+        cmap->lcluster_id_max < lcluster_id ||
+        cmap->lcluster[lcluster_id].fcluster_id == 0xffff
+    ) {
+        return -2;
+    }
+    fsector_addr  = cmap->lcluster[lcluster_id].fcluster_addr;
+    fsector_addr += (lsector_id % 8) * 512;
+    *sector = fsector_addr;
+    return 0;
+}
+
 /* fygue_flash_cmap_init() - initialize fcluster translation
  *
  * notes:
@@ -95,7 +122,7 @@ static int fygue_flash_cmap_update(
  * returns:
  *   -1 if the sector 0 is not found
  *    0 success */
-int fygue_flash_cmap_init(
+int fygue_flash_cmap_initialize(
     struct fygue_flash *flash,
     struct fygue_flash_cmap *cmap
 ) {
@@ -137,29 +164,16 @@ int fygue_flash_cmap_init(
     return 0;
 }
 
-/* fygue_flash_cmap_lsector_get_addr() - get logical sector address */
-int fygue_flash_cmap_lsector_get_addr(
+/* fygue_flash_cmap_sync() - sync the fcluster redirection map */
+int fygue_flash_cmap_sync(
     struct fygue_flash *flash,
-    struct fygue_flash_cmap *cmap,
-    uintptr_t *sector,
-    uint16_t lsector_id
+    struct fygue_flash_cmap *cmap
 ) {
-    uintptr_t fsector_addr;
-    uint16_t lcluster_id;
-
-    if (flash == NULL  || sector == NULL || cmap == NULL)
+    if (flash == NULL || cmap == NULL)
         return -1;
-    if (cmap->lcluster == NULL)
-        return -1;
-    lcluster_id = lsector_id / 8;
-    if (
-        cmap->lcluster_id_max < lcluster_id ||
-        cmap->lcluster[lcluster_id].fcluster_id == 0xffff
-    ) {
+    for (int i = 0 ; i < cmap->lcluster_id_max ; i++)
+        cmap->lcluster[i].version = 0xffffffff;
+    if (fygue_flash_cmap_initialize(flash, cmap) != 0)
         return -2;
-    }
-    fsector_addr  = cmap->lcluster[lcluster_id].fcluster_addr;
-    fsector_addr += (lsector_id % 8) * 512;
-    *sector = fsector_addr;
     return 0;
 }
diff --git a/src/fs/fygue/flash/flash.c b/src/fs/fygue/flash/flash.c
index 1302803..a3ffd34 100644
--- a/src/fs/fygue/flash/flash.c
+++ b/src/fs/fygue/flash/flash.c
@@ -36,9 +36,9 @@ int _fygue_flash_hw_detect(struct fygue_flash *flash)
             geometry->fsector_size = FYGUE_FSECTOR_SIZE_128K;
             break;
         case HWCALC_FXCG100:
-            geometry->phy_start = 0x00bc0000;
+            geometry->phy_start = 0x00c80000;
             geometry->fsector_size = FYGUE_FSECTOR_SIZE_128K;
-            geometry->fsector_count = 0x26;
+            geometry->fsector_count = 0x3d;
             break;
         default:
             errno = ENOTSUP;
@@ -69,7 +69,17 @@ int fygue_flash_initialize(struct fygue_flash *flash)
     memset(flash, 0x00, sizeof(struct fygue_flash));
     if (_fygue_flash_hw_detect(flash) != 0)
         return -2;
-    if (fygue_flash_cmap_init(flash, &(flash->cmap)) != 0)
+    if (fygue_flash_cmap_initialize(flash, &(flash->cmap)) != 0)
+        return -3;
+    return 0;
+}
+
+/* fygue_flash_sync(): re-init flash information */
+int fygue_flash_sync(struct fygue_flash *flash)
+{
+    if (flash == NULL)
+        return -1;
+    if (fygue_flash_cmap_sync(flash, &(flash->cmap)) != 0)
         return -3;
     return 0;
 }
diff --git a/src/fs/fygue/flash/flash.h b/src/fs/fygue/flash/flash.h
index 7224a43..677faee 100644
--- a/src/fs/fygue/flash/flash.h
+++ b/src/fs/fygue/flash/flash.h
@@ -62,6 +62,9 @@ struct fygue_flash
 /* fygue_flash_initialize(): init flash abstraction */
 extern int fygue_flash_initialize(struct fygue_flash *flash);
 
+/* fygue_flash_sync(): re-init flash information */
+extern int fygue_flash_sync(struct fygue_flash *flash);
+
 /* fygue_flash_sector_get_addr(): return the logical sector address */
 extern int fygue_flash_sector_get_addr(
     struct fygue_flash *flash,
@@ -73,8 +76,14 @@ extern int fygue_flash_sector_get_addr(
 // (internal) cluster map interface
 //---
 
-/* fygue_flash_cmap_init() - initialize the fcluster redirection map */
-extern int fygue_flash_cmap_init(
+/* fygue_flash_cmap_initialize() - initialize the fcluster redirection map */
+extern int fygue_flash_cmap_initialize(
+    struct fygue_flash *flash,
+    struct fygue_flash_cmap *cmap
+);
+
+/* fygue_flash_cmap_sync() - sync the fcluster redirection map */
+extern int fygue_flash_cmap_sync(
     struct fygue_flash *flash,
     struct fygue_flash_cmap *cmap
 );
diff --git a/src/fs/fygue/fygue.c b/src/fs/fygue/fygue.c
index e4ed053..72577b2 100644
--- a/src/fs/fygue/fygue.c
+++ b/src/fs/fygue/fygue.c
@@ -27,7 +27,7 @@ int fygue_mount(struct fygue_fsinfo **fsinfo, bool refresh)
         __fygue_fsinfo = calloc(1, sizeof(struct fygue_fsinfo));
         if (__fygue_fsinfo == NULL)
             return -2;
-        if (fygue_fat_init_cold(&(__fygue_fsinfo->fat)) != 0) {
+        if (fygue_fat_initialize(&(__fygue_fsinfo->fat)) != 0) {
             free(__fygue_fsinfo);
             __fygue_fsinfo = NULL;
             return -3;
@@ -35,7 +35,7 @@ int fygue_mount(struct fygue_fsinfo **fsinfo, bool refresh)
         __fygue_fsinfo->dirty = false;
     }
     if (refresh && __fygue_fsinfo->dirty) {
-        if (fygue_fat_init_hot(&(__fygue_fsinfo->fat)) != 0)
+        if (fygue_fat_sync(&(__fygue_fsinfo->fat)) != 0)
             return -4;
         __fygue_fsinfo->dirty = false;
     }
@@ -82,6 +82,34 @@ int fygue_resolve(char const * const path, struct fygue_resolve *resolve)
     return 0;
 }
 
+//---
+// Syncronization
+//---
+
+/* fygue_descriptor_sync(): sync internal descriptor information */
+int fygue_descriptor_sync(
+    struct fygue_fsinfo **fsinfo,
+    struct fygue_descriptor *desc
+) {
+    int (*sync)(struct fygue_descriptor*);
+    struct fygue_fsinfo *ffsinfo;
+
+    if (fygue_mount(&ffsinfo, true) != 0)
+        return -2;
+    if (fsinfo != NULL)
+        *fsinfo = ffsinfo;
+    if (desc != NULL && desc->dirty)
+    {
+        sync = &fygue_file_sync;
+        if (desc->resolve.type == FYGUE_FILE_TYPE_DIR)
+            sync = &fygue_dir_sync;
+        if (sync(desc) != 0)
+            return -1;
+        desc->dirty = false;
+    }
+    return 0;
+}
+
 //---
 // Descriptor
 //---
diff --git a/src/fs/fygue/fygue.h b/src/fs/fygue/fygue.h
index 6e1d931..d8ae317 100644
--- a/src/fs/fygue/fygue.h
+++ b/src/fs/fygue/fygue.h
@@ -65,7 +65,6 @@ struct fygue_resolve {
         struct {
             off_t cursor;
             struct fygue_fat_file fat;
-            off_t size;
         } file;
         struct {
             struct fygue_fat_dir fat;
@@ -88,6 +87,11 @@ struct fygue_descriptor
 /* fygue_mount(): mount and return the filesystem info */
 extern int fygue_mount(struct fygue_fsinfo **fsinfo, bool refresh);
 
+/* fygue_descriptor_sync(): sync internal descriptor information */
+extern int fygue_descriptor_sync(
+    struct fygue_fsinfo **fsinfo,
+    struct fygue_descriptor *desc
+);
 
 /* fygue_resolve() - try to resolve path */
 extern int fygue_resolve(
@@ -123,6 +127,9 @@ extern ssize_t fygue_dir_write(
 /* fygue_dir_close(): close directory */
 extern int fygue_dir_close(struct fygue_descriptor *desc);
 
+/* fygue_dir_sync(): directory-specific sync */
+extern int fygue_dir_sync(struct fygue_descriptor *desc);
+
 //---
 // File interface
 //---
@@ -151,6 +158,9 @@ extern ssize_t fygue_file_write(
 /* fygue_file_close(): close directory */
 extern int fygue_file_close(struct fygue_descriptor *desc);
 
+/* fygue_file_sync(): file-specific sync */
+extern int fygue_file_sync(struct fygue_descriptor *desc);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/fs/fygue/fygue_dir_close.c b/src/fs/fygue/fygue_dir_close.c
index 518607e..a2e670f 100644
--- a/src/fs/fygue/fygue_dir_close.c
+++ b/src/fs/fygue/fygue_dir_close.c
@@ -13,7 +13,7 @@ int fygue_dir_close(struct fygue_descriptor *desc)
         errno = EBADF;
         return -1;
     }
-    if (fygue_mount(&fsinfo, true) != 0) {
+    if (fygue_descriptor_sync(&fsinfo, desc) != 0) {
         errno = EIO;
         return -1;
     }
diff --git a/src/fs/fygue/fygue_dir_lseek.c b/src/fs/fygue/fygue_dir_lseek.c
index fa3184c..f1809e1 100644
--- a/src/fs/fygue/fygue_dir_lseek.c
+++ b/src/fs/fygue/fygue_dir_lseek.c
@@ -35,6 +35,10 @@ off_t fygue_dir_lseek(
         errno = EINVAL;
         return -1;
     }
+    if (fygue_descriptor_sync(NULL, desc) != 0) {
+        errno = EIO;
+        return -1;
+    }
     if(whence == SEEK_CUR)
         offset += desc->resolve.dir.pos;
     if(whence == SEEK_END) {
diff --git a/src/fs/fygue/fygue_dir_read.c b/src/fs/fygue/fygue_dir_read.c
index b72148c..7ff183f 100644
--- a/src/fs/fygue/fygue_dir_read.c
+++ b/src/fs/fygue/fygue_dir_read.c
@@ -77,7 +77,6 @@ int fygue_dir_read(
     int rc;
 
     ENOTSUP_IF_NOT_FYGUE(-1);
-
     if (desc == NULL || desc->resolve.type != FYGUE_FILE_TYPE_DIR) {
         errno = EBADF;
         return -1;
@@ -90,7 +89,7 @@ int fygue_dir_read(
         errno = EINVAL;
         return -1;
     }
-    if (fygue_mount(&fsinfo, true) != 0) {
+    if (fygue_descriptor_sync(&fsinfo, desc) != 0) {
         errno = EIO;
         return -1;
     }
diff --git a/src/fs/fygue/fygue_dir_sync.c b/src/fs/fygue/fygue_dir_sync.c
new file mode 100644
index 0000000..7b5a296
--- /dev/null
+++ b/src/fs/fygue/fygue_dir_sync.c
@@ -0,0 +1,33 @@
+#include <stdlib.h>
+#include "fygue.h"
+
+/* fygue_dir_sync(): directory-specific sync */
+int fygue_dir_sync(struct fygue_descriptor *desc)
+{
+    struct fygue_fsinfo *fsinfo;
+    int rc;
+
+    ENOTSUP_IF_NOT_FYGUE(-1);
+    if (desc == NULL || desc->resolve.type != FYGUE_FILE_TYPE_DIR) {
+        errno = EBADF;
+        return -1;
+    }
+    //if (desc->)
+    if (fygue_mount(&fsinfo, true)) {
+        errno = EIO;
+        return -1;
+    }
+    for (int i = 0 ; i < desc->resolve.dir.count ; i++) {
+        if (desc->resolve.dir.dirent[i] == NULL)
+            continue;
+        free(desc->resolve.dir.dirent[i]);
+        desc->resolve.dir.dirent[i] = NULL;
+    }
+    rc = fygue_fat_dir_sync(
+        &(fsinfo->fat),
+        &(desc->resolve.dir.fat)
+    );
+    if (rc != 0)
+        return -2;
+    return 0;
+}
diff --git a/src/fs/fygue/fygue_file_close.c b/src/fs/fygue/fygue_file_close.c
index 8f2ad8a..51131c2 100644
--- a/src/fs/fygue/fygue_file_close.c
+++ b/src/fs/fygue/fygue_file_close.c
@@ -13,7 +13,7 @@ int fygue_file_close(struct fygue_descriptor *desc)
         errno = EBADF;
         return -1;
     }
-    if (fygue_mount(&fsinfo, true) != 0) {
+    if (fygue_descriptor_sync(&fsinfo, desc) != 0) {
         errno = EIO;
         return -1;
     }
diff --git a/src/fs/fygue/fygue_file_lseek.c b/src/fs/fygue/fygue_file_lseek.c
index bd3da94..e4ff525 100644
--- a/src/fs/fygue/fygue_file_lseek.c
+++ b/src/fs/fygue/fygue_file_lseek.c
@@ -1,6 +1,6 @@
 #include "fygue.h"
 
-/* fygue_file_lseek(): seek directory */
+/* fygue_file_lseek(): seek file */
 off_t fygue_file_lseek(
     struct fygue_descriptor *desc,
     off_t offset,
@@ -17,7 +17,7 @@ off_t fygue_file_lseek(
         errno = EINVAL;
         return -1;
     }
-    if (fygue_mount(&fsinfo, true) != 0) {
+    if (fygue_descriptor_sync(&fsinfo, desc) != 0) {
         errno = EIO;
         return -1;
     }
diff --git a/src/fs/fygue/fygue_file_read.c b/src/fs/fygue/fygue_file_read.c
index 2a93995..1f8c18f 100644
--- a/src/fs/fygue/fygue_file_read.c
+++ b/src/fs/fygue/fygue_file_read.c
@@ -19,6 +19,10 @@ ssize_t fygue_file_read(
         errno = EFAULT;
         return -1;
     }
+    if (fygue_file_sync(desc) != 0) {
+        errno = EIO;
+        return -1;
+    }
     if (fygue_mount(&fsinfo, true) != 0) {
         errno = EIO;
         return -1;
diff --git a/src/fs/fygue/fygue_file_sync.c b/src/fs/fygue/fygue_file_sync.c
new file mode 100644
index 0000000..52d10a2
--- /dev/null
+++ b/src/fs/fygue/fygue_file_sync.c
@@ -0,0 +1,26 @@
+#include "fygue.h"
+
+/* fygue_file_sync(): file-specific sync */
+int fygue_file_sync(struct fygue_descriptor *desc)
+{
+    struct fygue_fsinfo *fsinfo;
+    int rc;
+
+    ENOTSUP_IF_NOT_FYGUE(-1);
+    if (desc == NULL || desc->resolve.type != FYGUE_FILE_TYPE_FILE) {
+        errno = EBADF;
+        return -1;
+    }
+    if (fygue_mount(&fsinfo, true)) {
+        errno = EIO;
+        return -1;
+    }
+    // nothing to sync in high-level
+    rc = fygue_fat_file_sync(
+        &(fsinfo->fat),
+        &(desc->resolve.file.fat)
+    );
+    if (rc != 0)
+        return -1;
+    return 0;
+}
diff --git a/src/fs/fygue/fygue_stat.c b/src/fs/fygue/fygue_stat.c
index 2028dd6..97f867c 100644
--- a/src/fs/fygue/fygue_stat.c
+++ b/src/fs/fygue/fygue_stat.c
@@ -16,7 +16,6 @@ int fygue_stat(char const * const path, struct stat *statbuf)
         errno = EIO;
         return -1;
     }
-
     if (fygue_resolve(path, &resolve) != 0) {
         errno = ENOENT;
         return -1;