diff --git a/bsp/beaglebone/rtconfig.h b/bsp/beaglebone/rtconfig.h
index 31f04a79c..bdb79ef05 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 4c0d4579f..ed31025f9 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 ec1513067..427c4894e 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 2d501d094..eb7e3e640 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 e421f9acb..13f7759b0 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 ce8d0dc90..5b0ea71b8 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 77846191f..c48cf2525 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 31854ca2f..9bb1b656f 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 94ac2093c..bd231931e 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 7490da534..bb73a21f8 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 d6fed266e..8bca3ee9a 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 9f4be59ff..fa8f5a301 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 0b5ea9732..78f5c51f6 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 9ef916998..2b196b446 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 78aa0e1dc..a4189b930 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 531ee3618..70c68f340 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 f59985817..817f24fee 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 c00e4537a..6da197d33 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 455cfcb11..fb83405df 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 84fc28028..8adbc4e57 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 84fc28028..8adbc4e57 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 bf078f704..4c042a88f 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