diff --git a/app/platform/common.c b/app/platform/common.c
index 617f6831..bb10fb45 100644
--- a/app/platform/common.c
+++ b/app/platform/common.c
@@ -102,15 +102,14 @@ extern char _flash_used_end[];
 // Return the sector number, as well as the start and end address of the sector
 static uint32_t flashh_find_sector( uint32_t address, uint32_t *pstart, uint32_t *pend )
 {
-  address -= INTERNAL_FLASH_START_ADDRESS;
 #ifdef INTERNAL_FLASH_SECTOR_SIZE
   // All the sectors in the flash have the same size, so just align the address
   uint32_t sect_id = address / INTERNAL_FLASH_SECTOR_SIZE;
 
   if( pstart )
-    *pstart = sect_id * INTERNAL_FLASH_SECTOR_SIZE + INTERNAL_FLASH_START_ADDRESS;
+    *pstart = sect_id * INTERNAL_FLASH_SECTOR_SIZE ;
   if( pend )
-    *pend = ( sect_id + 1 ) * INTERNAL_FLASH_SECTOR_SIZE + INTERNAL_FLASH_START_ADDRESS - 1;
+    *pend = ( sect_id + 1 ) * INTERNAL_FLASH_SECTOR_SIZE - 1;
   return sect_id;
 #else // #ifdef INTERNAL_FLASH_SECTOR_SIZE
   // The flash has blocks of different size
@@ -121,9 +120,9 @@ static uint32_t flashh_find_sector( uint32_t address, uint32_t *pstart, uint32_t
   while( ( total <= address ) && ( i < sizeof( flash_sect_size ) / sizeof( uint32_t ) ) )
     total += flash_sect_size[ i ++ ];
   if( pstart )
-    *pstart = ( total - flash_sect_size[ i - 1 ] ) + INTERNAL_FLASH_START_ADDRESS;
+    *pstart = ( total - flash_sect_size[ i - 1 ] );
   if( pend )
-    *pend = total + INTERNAL_FLASH_START_ADDRESS - 1;
+    *pend = total - 1;
   return i - 1;
 #endif // #ifdef INTERNAL_FLASH_SECTOR_SIZE
 }
@@ -150,13 +149,12 @@ uint32_t platform_flash_get_first_free_block_address( uint32_t *psect )
   uint32_t start, end, sect;
   NODE_DBG("_flash_used_end:%08x\n", (uint32_t)_flash_used_end);
   if(_flash_used_end>0){ // find the used sector
-    // sect = flashh_find_sector( ( uint32_t )flash_used_size + INTERNAL_FLASH_START_ADDRESS - 1, NULL, &end );
-    sect = flashh_find_sector( ( uint32_t )_flash_used_end - 1, NULL, &end );
+    sect = flashh_find_sector( ( uint32_t )_flash_used_end - INTERNAL_FLASH_MAPPED_ADDRESS - 1, NULL, &end );
     if( psect )
       *psect = sect + 1;    
     return end + 1;
   }else{
-    sect = flashh_find_sector( INTERNAL_FLASH_START_ADDRESS, &start, NULL ); // find the first free sector
+    sect = flashh_find_sector( 0, &start, NULL ); // find the first free sector
     if( psect )
       *psect = sect;   
     return start;
diff --git a/app/platform/cpu_esp8266.h b/app/platform/cpu_esp8266.h
index ec6440a7..ef618dea 100644
--- a/app/platform/cpu_esp8266.h
+++ b/app/platform/cpu_esp8266.h
@@ -53,7 +53,7 @@
 #define INTERNAL_FLASH_READ_UNIT_SIZE	4
 
 #define INTERNAL_FLASH_SIZE             ( (SYS_PARAM_SEC_START) * INTERNAL_FLASH_SECTOR_SIZE )
-#define INTERNAL_FLASH_START_ADDRESS    0x40200000
+#define INTERNAL_FLASH_MAPPED_ADDRESS    0x40200000
 
 // SpiFlashOpResult spi_flash_erase_sector(uint16 sec);
 // SpiFlashOpResult spi_flash_write(uint32 des_addr, uint32 *src_addr, uint32 size);
diff --git a/app/platform/flash_api.c b/app/platform/flash_api.c
index 985b2c5f..5955be26 100644
--- a/app/platform/flash_api.c
+++ b/app/platform/flash_api.c
@@ -96,11 +96,6 @@ SpiFlashOpResult flash_safe_erase_sector(uint16 sec)
 SPIFlashInfo flash_rom_getinfo(void)
 {
     volatile SPIFlashInfo spi_flash_info ICACHE_STORE_ATTR;
-    // Don't use it before cache read disabled
-    // FLASH_DISABLE_CACHE();
-    // spi_flash_info = *((SPIFlashInfo *)(FLASH_ADDRESS_START_MAP));
-    // FLASH_ENABLE_CACHE();
-    // Needn't safe mode.
     spi_flash_read(0, (uint32 *)(& spi_flash_info), sizeof(spi_flash_info));
     return spi_flash_info;
 }
diff --git a/app/platform/flash_api.h b/app/platform/flash_api.h
index 0063ee1c..99339ee3 100644
--- a/app/platform/flash_api.h
+++ b/app/platform/flash_api.h
@@ -4,8 +4,6 @@
 #include "user_config.h"
 #include "cpu_esp8266.h"
 
-#define FLASH_ADDRESS_START_MAP (INTERNAL_FLASH_START_ADDRESS)
-
 #define FLASH_SIZE_2MBIT    (2   * 1024 * 1024)
 #define FLASH_SIZE_4MBIT    (4   * 1024 * 1024)
 #define FLASH_SIZE_8MBIT    (8   * 1024 * 1024)
diff --git a/app/platform/platform.c b/app/platform/platform.c
index 3d776f3a..1a45d5b1 100755
--- a/app/platform/platform.c
+++ b/app/platform/platform.c
@@ -514,12 +514,11 @@ int platform_spi_transaction( uint8_t id, uint8_t cmd_bitlen, spi_data_type cmd_
  */
 uint32_t platform_s_flash_write( const void *from, uint32_t toaddr, uint32_t size )
 {
-  toaddr -= INTERNAL_FLASH_START_ADDRESS;
   SpiFlashOpResult r;
   const uint32_t blkmask = INTERNAL_FLASH_WRITE_UNIT_SIZE - 1;
   uint32_t *apbuf = NULL;
   uint32_t fromaddr = (uint32_t)from;
-  if( (fromaddr & blkmask ) || (fromaddr >= INTERNAL_FLASH_START_ADDRESS)) {
+  if( (fromaddr & blkmask ) || (fromaddr >= INTERNAL_FLASH_MAPPED_ADDRESS)) {
     apbuf = (uint32_t *)c_malloc(size);
     if(!apbuf)
       return 0;
@@ -532,7 +531,7 @@ uint32_t platform_s_flash_write( const void *from, uint32_t toaddr, uint32_t siz
   if(SPI_FLASH_RESULT_OK == r)
     return size;
   else{
-    NODE_ERR( "ERROR in flash_write: r=%d at %08X\n", ( int )r, ( unsigned )toaddr+INTERNAL_FLASH_START_ADDRESS );
+    NODE_ERR( "ERROR in flash_write: r=%d at %08X\n", ( int )r, ( unsigned )toaddr);
     return 0;
   }
 }
@@ -547,7 +546,6 @@ uint32_t platform_s_flash_read( void *to, uint32_t fromaddr, uint32_t size )
   if (size==0)
     return 0;
 
-  fromaddr -= INTERNAL_FLASH_START_ADDRESS;
   SpiFlashOpResult r;
   system_soft_wdt_feed ();
 
@@ -571,7 +569,7 @@ uint32_t platform_s_flash_read( void *to, uint32_t fromaddr, uint32_t size )
   if(SPI_FLASH_RESULT_OK == r)
     return size;
   else{
-    NODE_ERR( "ERROR in flash_read: r=%d at %08X\n", ( int )r, ( unsigned )fromaddr+INTERNAL_FLASH_START_ADDRESS );
+    NODE_ERR( "ERROR in flash_read: r=%d at %08X\n", ( int )r, ( unsigned )fromaddr);
     return 0;
   }
 }
diff --git a/app/spiffs/spiffs.c b/app/spiffs/spiffs.c
index 03436193..f5c514f7 100644
--- a/app/spiffs/spiffs.c
+++ b/app/spiffs/spiffs.c
@@ -53,7 +53,7 @@ void myspiffs_mount() {
 #endif
   cfg.phys_addr += 0x3000;
   cfg.phys_addr &= 0xFFFFC000;  // align to 4 sector.
-  cfg.phys_size = INTERNAL_FLASH_SIZE - ( ( u32_t )cfg.phys_addr - INTERNAL_FLASH_START_ADDRESS );
+  cfg.phys_size = INTERNAL_FLASH_SIZE - ( ( u32_t )cfg.phys_addr );
   cfg.phys_erase_block = INTERNAL_FLASH_SECTOR_SIZE; // according to datasheet
   cfg.log_block_size = INTERNAL_FLASH_SECTOR_SIZE; // let us not complicate things
   cfg.log_page_size = LOG_PAGE_SIZE; // as we said
@@ -97,7 +97,7 @@ int myspiffs_format( void )
   sect_first += 0x3000;
   sect_first &= 0xFFFFC000;  // align to 4 sector.
   sect_first = platform_flash_get_sector_of_address(sect_first);
-  sect_last = INTERNAL_FLASH_SIZE + INTERNAL_FLASH_START_ADDRESS - 4;
+  sect_last = INTERNAL_FLASH_SIZE - SYS_PARAM_SEC_NUM;
   sect_last = platform_flash_get_sector_of_address(sect_last);
   NODE_DBG("sect_first: %x, sect_last: %x\n", sect_first, sect_last);
   while( sect_first <= sect_last )
diff --git a/app/wofs/romfs.c b/app/wofs/romfs.c
index 41faad05..75558d63 100644
--- a/app/wofs/romfs.c
+++ b/app/wofs/romfs.c
@@ -521,7 +521,7 @@ int romfs_init( void )
 #if defined( BUILD_WOFS ) 
   // Get the start address and size of WOFS and register it
   wofs_fsdata.pbase = ( uint8_t* )platform_flash_get_first_free_block_address( NULL );
-  wofs_fsdata.max_size = INTERNAL_FLASH_SIZE - ( ( uint32_t )wofs_fsdata.pbase - INTERNAL_FLASH_START_ADDRESS );
+  wofs_fsdata.max_size = INTERNAL_FLASH_SIZE - ( ( uint32_t )wofs_fsdata.pbase );
   NODE_DBG("wofs.pbase:%x,max:%x\n",wofs_fsdata.pbase,wofs_fsdata.max_size);
 #endif // ifdef BUILD_WOFS
   return 0;