diff --git a/bsp/beaglebone/rtconfig.h b/bsp/beaglebone/rtconfig.h
index 31f04a79c7c614b6c82c06bdb16ff64e3fbf428e..bdb79ef054c47809afa9b8e369fd4b38150d774f 100644
--- a/bsp/beaglebone/rtconfig.h
+++ b/bsp/beaglebone/rtconfig.h
@@ -145,7 +145,7 @@
 // <item description="LFN1">2</item>
 // </integer>
 #define RT_DFS_ELM_USE_LFN	1
-// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="256" />
+// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="255" />
 #define RT_DFS_ELM_MAX_LFN	64
 // <bool name="RT_USING_DFS_YAFFS2" description="Using YAFFS2" default="false" />
 // #define RT_USING_DFS_YAFFS2
diff --git a/bsp/fh8620/rtconfig.h b/bsp/fh8620/rtconfig.h
index 4c0d4579f21af6390c6630e581d64caac07871ca..ed31025f939a8475f22bddd37c96c72895e7992e 100644
--- a/bsp/fh8620/rtconfig.h
+++ b/bsp/fh8620/rtconfig.h
@@ -139,8 +139,8 @@
 #define RT_DFS_ELM_CODE_PAGE	936
 // <bool name="RT_DFS_ELM_CODE_PAGE_FILE" description="Using OEM code page file" default="false" />
 #define RT_DFS_ELM_CODE_PAGE_FILE
-// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="256" />
-#define RT_DFS_ELM_MAX_LFN	256
+// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="255" />
+#define RT_DFS_ELM_MAX_LFN	255
 // <integer name="RT_DFS_ELM_MAX_SECTOR_SIZE" description="Maximal size of sector" default="512" />
 #define RT_DFS_ELM_MAX_SECTOR_SIZE  4096
 // <bool name="RT_USING_DFS_YAFFS2" description="Using YAFFS2" default="false" />
diff --git a/bsp/imx6sx/cortex-a9/rtconfig.h b/bsp/imx6sx/cortex-a9/rtconfig.h
index ec15130670c091c313fd0c8b066cb3b8ad798751..427c4894e0879f86b3670e115a41cd167ee534e6 100644
--- a/bsp/imx6sx/cortex-a9/rtconfig.h
+++ b/bsp/imx6sx/cortex-a9/rtconfig.h
@@ -128,7 +128,7 @@
 // <item description="LFN1">2</item>
 // </integer>
 #define RT_DFS_ELM_USE_LFN	1
-// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="256" />
+// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="255" />
 #define RT_DFS_ELM_MAX_LFN	64
 // <bool name="RT_USING_DFS_YAFFS2" description="Using YAFFS2" default="false" />
 // #define RT_USING_DFS_YAFFS2
diff --git a/bsp/lpc176x/rtconfig.h b/bsp/lpc176x/rtconfig.h
index 2d501d09433470b23763f0ee75c9da169ac7d547..eb7e3e6401dd153a93ec73b0efee5dc5fdf4e90b 100644
--- a/bsp/lpc176x/rtconfig.h
+++ b/bsp/lpc176x/rtconfig.h
@@ -140,7 +140,7 @@
 // <item description="ASCII only (Valid for non LFN cfg.)">1</item>
 // </integer>
 #define RT_DFS_ELM_CODE_PAGE 437
-// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="256" />
+// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="255" />
 #define RT_DFS_ELM_MAX_LFN	64
 // <bool name="RT_USING_DFS_YAFFS2" description="Using YAFFS2" default="false" />
 // #define RT_USING_DFS_YAFFS2
diff --git a/bsp/lpc178x/rtconfig.h b/bsp/lpc178x/rtconfig.h
index e421f9acb00f42ac0eebcffa0f4260eaf9cbbfbf..13f7759b0b781de37bae8804689e996ba77d847e 100644
--- a/bsp/lpc178x/rtconfig.h
+++ b/bsp/lpc178x/rtconfig.h
@@ -108,7 +108,7 @@
 // <item description="LFN1">2</item>
 // </integer>
 #define RT_DFS_ELM_USE_LFN	1
-// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="256" />
+// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="255" />
 #define RT_DFS_ELM_MAX_LFN	64
 // <bool name="RT_USING_DFS_YAFFS2" description="Using YAFFS2" default="false" />
 // #define RT_USING_DFS_YAFFS2
diff --git a/bsp/lpc408x/rtconfig.h b/bsp/lpc408x/rtconfig.h
index ce8d0dc9083da01933ac36b8f335e830e5ad9685..5b0ea71b8ae937ee1817b339cca92f1f65061a02 100644
--- a/bsp/lpc408x/rtconfig.h
+++ b/bsp/lpc408x/rtconfig.h
@@ -136,8 +136,8 @@
 #define RT_DFS_ELM_CODE_PAGE	936
 // <bool name="RT_DFS_ELM_CODE_PAGE_FILE" description="Using OEM code page file" default="false" />
 #define RT_DFS_ELM_CODE_PAGE_FILE
-// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="256" />
-#define RT_DFS_ELM_MAX_LFN	256
+// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="255" />
+#define RT_DFS_ELM_MAX_LFN	255
 // <integer name="RT_DFS_ELM_MAX_SECTOR_SIZE" description="Maximal size of sector" default="512" />
 #define RT_DFS_ELM_MAX_SECTOR_SIZE  4096
 // <bool name="RT_USING_DFS_YAFFS2" description="Using YAFFS2" default="false" />
diff --git a/bsp/lpc43xx/M0/rtconfig.h b/bsp/lpc43xx/M0/rtconfig.h
index 77846191fc56628d5687cc685d4820c2fbe727b6..c48cf2525c843725984f9409db938cad06bca057 100644
--- a/bsp/lpc43xx/M0/rtconfig.h
+++ b/bsp/lpc43xx/M0/rtconfig.h
@@ -147,8 +147,8 @@
 #define RT_DFS_ELM_CODE_PAGE    936
 // <bool name="RT_DFS_ELM_CODE_PAGE_FILE" description="Using OEM code page file" default="false" />
 #define RT_DFS_ELM_CODE_PAGE_FILE
-// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="256" />
-#define RT_DFS_ELM_MAX_LFN  256
+// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="255" />
+#define RT_DFS_ELM_MAX_LFN  255
 // <integer name="RT_DFS_ELM_MAX_SECTOR_SIZE" description="Maximal size of sector" default="512" />
 #define RT_DFS_ELM_MAX_SECTOR_SIZE  4096
 // <bool name="RT_DFS_ELM_USE_ERASE" description="Enable erase feature for flash" default="true" />
diff --git a/bsp/lpc43xx/M4/rtconfig.h b/bsp/lpc43xx/M4/rtconfig.h
index 31854ca2fccef0029f556435a7fe235fa3ca5792..9bb1b656f204a332f874d678b5d4a05f899d0f80 100644
--- a/bsp/lpc43xx/M4/rtconfig.h
+++ b/bsp/lpc43xx/M4/rtconfig.h
@@ -146,8 +146,8 @@
 #define RT_DFS_ELM_CODE_PAGE    936
 // <bool name="RT_DFS_ELM_CODE_PAGE_FILE" description="Using OEM code page file" default="false" />
 #define RT_DFS_ELM_CODE_PAGE_FILE
-// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="256" />
-#define RT_DFS_ELM_MAX_LFN  256
+// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="255" />
+#define RT_DFS_ELM_MAX_LFN  255
 // <integer name="RT_DFS_ELM_MAX_SECTOR_SIZE" description="Maximal size of sector" default="512" />
 #define RT_DFS_ELM_MAX_SECTOR_SIZE  4096
 // <bool name="RT_DFS_ELM_USE_ERASE" description="Enable erase feature for flash" default="true" />
diff --git a/bsp/lpc5410x/rtconfig.h b/bsp/lpc5410x/rtconfig.h
index 94ac2093cdacdfa5ca0068694ccf6625ab724e05..bd231931e3ef874b7b3c31d0352d993197e4f884 100644
--- a/bsp/lpc5410x/rtconfig.h
+++ b/bsp/lpc5410x/rtconfig.h
@@ -110,7 +110,7 @@
 // <item description="LFN1">2</item>
 // </integer>
 #define RT_DFS_ELM_USE_LFN	1
-// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="256" />
+// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="255" />
 #define RT_DFS_ELM_MAX_LFN	64
 // <bool name="RT_USING_DFS_YAFFS2" description="Using YAFFS2" default="false" />
 // #define RT_USING_DFS_YAFFS2
diff --git a/bsp/ls1bdev/rtconfig.h b/bsp/ls1bdev/rtconfig.h
index 7490da534e8dff4a43b29313b0ff7f25c4fc54db..bb73a21f82db39a0a9eecfada60e854a1f229ac8 100644
--- a/bsp/ls1bdev/rtconfig.h
+++ b/bsp/ls1bdev/rtconfig.h
@@ -114,7 +114,7 @@
 // <item description="LFN1">2</item>
 // </integer>
 #define RT_DFS_ELM_USE_LFN	1
-// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="256" />
+// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="255" />
 #define RT_DFS_ELM_MAX_LFN	64
 // <bool name="RT_USING_DFS_YAFFS2" description="Using YAFFS2" default="false" />
 // #define RT_USING_DFS_YAFFS2
diff --git a/bsp/ls1cdev/rtconfig.h b/bsp/ls1cdev/rtconfig.h
index d6fed266e6f8e57a899b2e596c445c6e42bb335d..8bca3ee9a01b846a48b1859b47a4c3f09412e80e 100644
--- a/bsp/ls1cdev/rtconfig.h
+++ b/bsp/ls1cdev/rtconfig.h
@@ -120,7 +120,7 @@
 // <item description="LFN1">2</item>
 // </integer>
 #define RT_DFS_ELM_USE_LFN	1
-// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="256" />
+// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="255" />
 #define RT_DFS_ELM_MAX_LFN	64
 // <bool name="RT_USING_DFS_YAFFS2" description="Using YAFFS2" default="false" />
 // #define RT_USING_DFS_YAFFS2
diff --git a/bsp/mb9bf506r/rtconfig.h b/bsp/mb9bf506r/rtconfig.h
index 9f4be59ff0773e874a51ce1489404ddeb6902dce..fa8f5a30140a95aa5df15bac9861eed36c8a8deb 100644
--- a/bsp/mb9bf506r/rtconfig.h
+++ b/bsp/mb9bf506r/rtconfig.h
@@ -154,7 +154,7 @@
 // <item description="LFN1">2</item>
 // </integer>
 #define RT_DFS_ELM_USE_LFN	1
-// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="256" />
+// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="255" />
 #define RT_DFS_ELM_MAX_LFN	64
 // <bool name="RT_USING_DFS_YAFFS2" description="Using YAFFS2" default="false" />
 // #define RT_USING_DFS_YAFFS2
diff --git a/bsp/mini2440/rtconfig.h b/bsp/mini2440/rtconfig.h
index 0b5ea9732bc9fbbebd5e86ae715f4f123234ef33..78f5c51f60d6486e13e9cfc106220563b88914d2 100644
--- a/bsp/mini2440/rtconfig.h
+++ b/bsp/mini2440/rtconfig.h
@@ -112,8 +112,8 @@
 #define RT_DFS_ELM_CODE_PAGE	936
 // <bool name="RT_DFS_ELM_CODE_PAGE_FILE" description="Using OEM code page file" default="false" />
 // #define RT_DFS_ELM_CODE_PAGE_FILE
-// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="256" />
-#define RT_DFS_ELM_MAX_LFN	256
+// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="255" />
+#define RT_DFS_ELM_MAX_LFN	255
 // <bool name="RT_USING_DFS_YAFFS2" description="Using YAFFS2" default="false" />
 // #define RT_USING_DFS_YAFFS2
 // <bool name="RT_USING_DFS_UFFS" description="Using UFFS" default="false" />
diff --git a/bsp/realview-a8/rtconfig.h b/bsp/realview-a8/rtconfig.h
index 9ef916998e8e02375d133818035cc44491a2ff29..2b196b44664ba388674e37d0f5edd6082fe70257 100644
--- a/bsp/realview-a8/rtconfig.h
+++ b/bsp/realview-a8/rtconfig.h
@@ -128,7 +128,7 @@
 // <item description="LFN1">2</item>
 // </integer>
 #define RT_DFS_ELM_USE_LFN	1
-// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="256" />
+// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="255" />
 #define RT_DFS_ELM_MAX_LFN	64
 // <bool name="RT_USING_DFS_YAFFS2" description="Using YAFFS2" default="false" />
 // #define RT_USING_DFS_YAFFS2
diff --git a/bsp/rm48x50/rtconfig.h b/bsp/rm48x50/rtconfig.h
index 78aa0e1dcf6dfd58e97f464bfd8a8d613a8eae8a..a4189b93089af62f32f4ab179e051e66fac0aaad 100644
--- a/bsp/rm48x50/rtconfig.h
+++ b/bsp/rm48x50/rtconfig.h
@@ -116,7 +116,7 @@
 // <item description="LFN1">2</item>
 // </integer>
 #define RT_DFS_ELM_USE_LFN	1
-// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="256" />
+// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="255" />
 #define RT_DFS_ELM_MAX_LFN	64
 // <bool name="RT_USING_DFS_YAFFS2" description="Using YAFFS2" default="false" />
 // #define RT_USING_DFS_YAFFS2
diff --git a/bsp/simulator/rtconfig.h b/bsp/simulator/rtconfig.h
index 531ee3618527165655488c5011f1f901abd4377e..70c68f34031f0cdc9c5144dd6d63f75deac7a0ce 100755
--- a/bsp/simulator/rtconfig.h
+++ b/bsp/simulator/rtconfig.h
@@ -120,7 +120,7 @@
 #define RT_DFS_ELM_USE_LFN	3
 // <integer name="RT_DFS_ELM_CODE_PAGE" description="OEM code page" default="437">
 #define RT_DFS_ELM_CODE_PAGE	437
-// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="256" />
+// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="255" />
 #define RT_DFS_ELM_MAX_LFN	128
 // <bool name="RT_USING_DFS_YAFFS2" description="Using YAFFS2" default="false" />
 // #define RT_USING_DFS_YAFFS2
diff --git a/bsp/stm32f7-disco/rtconfig.h b/bsp/stm32f7-disco/rtconfig.h
index f599858171479d351e12d62428553a1fa87c1ff0..817f24fee34fc7a4e2a1b8f12e30f67d081de24e 100644
--- a/bsp/stm32f7-disco/rtconfig.h
+++ b/bsp/stm32f7-disco/rtconfig.h
@@ -145,8 +145,8 @@
 #define RT_DFS_ELM_CODE_PAGE	437
 // <bool name="RT_DFS_ELM_CODE_PAGE_FILE" description="Using OEM code page file" default="false" />
 // #define RT_DFS_ELM_CODE_PAGE_FILE
-// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="256" />
-#define RT_DFS_ELM_MAX_LFN	256
+// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="255" />
+#define RT_DFS_ELM_MAX_LFN	255
 // <integer name="RT_DFS_ELM_MAX_SECTOR_SIZE" description="Maximal size of sector" default="512" />
 #define RT_DFS_ELM_MAX_SECTOR_SIZE  4096
 // <bool name="RT_DFS_ELM_USE_ERASE" description="Enable erase feature for flash" default="true" />
diff --git a/bsp/tm4c129x/rtconfig.h b/bsp/tm4c129x/rtconfig.h
index c00e4537ad6c517913106a13a09a2eb6f8831984..6da197d331aa1701ebb48e5ec8eea7d328264893 100644
--- a/bsp/tm4c129x/rtconfig.h
+++ b/bsp/tm4c129x/rtconfig.h
@@ -145,8 +145,8 @@
 #define RT_DFS_ELM_CODE_PAGE    936
 // <bool name="RT_DFS_ELM_CODE_PAGE_FILE" description="Using OEM code page file" default="false" />
 #define RT_DFS_ELM_CODE_PAGE_FILE
-// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="256" />
-#define RT_DFS_ELM_MAX_LFN  256
+// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="255" />
+#define RT_DFS_ELM_MAX_LFN  255
 // <integer name="RT_DFS_ELM_MAX_SECTOR_SIZE" description="Maximal size of sector" default="512" />
 #define RT_DFS_ELM_MAX_SECTOR_SIZE  4096
 // <bool name="RT_DFS_ELM_USE_ERASE" description="Enable erase feature for flash" default="true" />
diff --git a/bsp/x1000/rtconfig.h b/bsp/x1000/rtconfig.h
index 455cfcb11e3923c8d5cf71cc2d890b5fbfc5c434..fb83405dfb446fd522cac2dbf92597e5d0e31687 100644
--- a/bsp/x1000/rtconfig.h
+++ b/bsp/x1000/rtconfig.h
@@ -139,8 +139,8 @@
 #define RT_DFS_ELM_USE_LFN	    3
 // <integer name="RT_DFS_ELM_CODE_PAGE" description="OEM code page" default="936">
 #define RT_DFS_ELM_CODE_PAGE	437
-// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="256" />
-#define RT_DFS_ELM_MAX_LFN	    256
+// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="255" />
+#define RT_DFS_ELM_MAX_LFN	    255
 // <bool name="RT_USING_DFS_YAFFS2" description="Using YAFFS2" default="false" />
 // #define RT_USING_DFS_YAFFS2
 // <bool name="RT_USING_DFS_UFFS" description="Using UFFS" default="false" />
diff --git a/bsp/xplorer4330/M0/rtconfig.h b/bsp/xplorer4330/M0/rtconfig.h
index 84fc28028c140a3eea4cf627bbe05421977ff9ca..8adbc4e576201c11eaceb7cb2ee9724bfa015016 100644
--- a/bsp/xplorer4330/M0/rtconfig.h
+++ b/bsp/xplorer4330/M0/rtconfig.h
@@ -145,8 +145,8 @@
 #define RT_DFS_ELM_CODE_PAGE    936
 // <bool name="RT_DFS_ELM_CODE_PAGE_FILE" description="Using OEM code page file" default="false" />
 #define RT_DFS_ELM_CODE_PAGE_FILE
-// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="256" />
-#define RT_DFS_ELM_MAX_LFN  256
+// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="255" />
+#define RT_DFS_ELM_MAX_LFN  255
 // <integer name="RT_DFS_ELM_MAX_SECTOR_SIZE" description="Maximal size of sector" default="512" />
 #define RT_DFS_ELM_MAX_SECTOR_SIZE  4096
 // <bool name="RT_DFS_ELM_USE_ERASE" description="Enable erase feature for flash" default="true" />
diff --git a/bsp/xplorer4330/M4/rtconfig.h b/bsp/xplorer4330/M4/rtconfig.h
index 84fc28028c140a3eea4cf627bbe05421977ff9ca..8adbc4e576201c11eaceb7cb2ee9724bfa015016 100644
--- a/bsp/xplorer4330/M4/rtconfig.h
+++ b/bsp/xplorer4330/M4/rtconfig.h
@@ -145,8 +145,8 @@
 #define RT_DFS_ELM_CODE_PAGE    936
 // <bool name="RT_DFS_ELM_CODE_PAGE_FILE" description="Using OEM code page file" default="false" />
 #define RT_DFS_ELM_CODE_PAGE_FILE
-// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="256" />
-#define RT_DFS_ELM_MAX_LFN  256
+// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="255" />
+#define RT_DFS_ELM_MAX_LFN  255
 // <integer name="RT_DFS_ELM_MAX_SECTOR_SIZE" description="Maximal size of sector" default="512" />
 #define RT_DFS_ELM_MAX_SECTOR_SIZE  4096
 // <bool name="RT_DFS_ELM_USE_ERASE" description="Enable erase feature for flash" default="true" />
diff --git a/bsp/zynq7000/rtconfig.h b/bsp/zynq7000/rtconfig.h
index bf078f70456025f838d320ee19f3b8955bf786ca..4c042a88f6c55d778a1dcb579c4b095957588a57 100644
--- a/bsp/zynq7000/rtconfig.h
+++ b/bsp/zynq7000/rtconfig.h
@@ -124,7 +124,7 @@
 // <item description="LFN1">2</item>
 // </integer>
 #define RT_DFS_ELM_USE_LFN	1
-// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="256" />
+// <integer name="RT_DFS_ELM_MAX_LFN" description="Maximal size of file name length" default="255" />
 #define RT_DFS_ELM_MAX_LFN	64
 // <bool name="RT_USING_DFS_YAFFS2" description="Using YAFFS2" default="false" />
 // #define RT_USING_DFS_YAFFS2