diff --git a/bsp/stm32f7-disco/SConstruct b/bsp/stm32f7-disco/SConstruct
index 6ea007ee9..af8f4a90b 100644
--- a/bsp/stm32f7-disco/SConstruct
+++ b/bsp/stm32f7-disco/SConstruct
@@ -20,6 +20,7 @@ TARGET = 'rtthread-stm32f7xx.' + rtconfig.TARGET_EXT
 env = Environment(tools = ['mingw'],
 	AS = rtconfig.AS, ASFLAGS = rtconfig.AFLAGS,
 	CC = rtconfig.CC, CCFLAGS = rtconfig.CFLAGS,
+	CXX = rtconfig.CXX, CXXFLAGS = rtconfig.CXXFLAGS,
 	AR = rtconfig.AR, ARFLAGS = '-rc',
 	LINK = rtconfig.LINK, LINKFLAGS = rtconfig.LFLAGS)
 env.PrependENVPath('PATH', rtconfig.EXEC_PATH)
diff --git a/bsp/stm32f7-disco/applications/SConscript b/bsp/stm32f7-disco/applications/SConscript
index 7e46cf27f..7a6bbeceb 100644
--- a/bsp/stm32f7-disco/applications/SConscript
+++ b/bsp/stm32f7-disco/applications/SConscript
@@ -3,7 +3,7 @@ from building import *
 cwd = GetCurrentDir()
 src = Glob('*.c')
 
-CPPPATH = [cwd]
+CPPPATH = [cwd, str(Dir('#'))]
 
 group = DefineGroup('Applications', src, depend = [''], CPPPATH = CPPPATH)
 
diff --git a/bsp/stm32f7-disco/applications/application.c b/bsp/stm32f7-disco/applications/application.c
index c8491a53f..e1dafdf5b 100644
--- a/bsp/stm32f7-disco/applications/application.c
+++ b/bsp/stm32f7-disco/applications/application.c
@@ -26,35 +26,9 @@
 #include <rtthread.h>
 #include <components.h>
 
-#include "drv_led.h"
-
-static void led_thread_entry(void *parameter)
-{
-
-    led_hw_init();
-
-    while (1)
-    {
-        led_on();
-        rt_thread_delay(RT_TICK_PER_SECOND);
-        led_off();
-        rt_thread_delay(RT_TICK_PER_SECOND);
-    }
-}
-
 void rt_init_thread_entry(void *parameter)
 {
-
-    rt_thread_t tid;
-
     rt_components_init();
-
-    tid = rt_thread_create("led",
-                           led_thread_entry, RT_NULL,
-                           512, 12, 5);
-
-    if (tid != RT_NULL)
-        rt_thread_startup(tid);
 }
 
 int rt_application_init()
@@ -64,11 +38,7 @@ int rt_application_init()
     tid = rt_thread_create("init",
                            rt_init_thread_entry, RT_NULL,
                            2048, RT_THREAD_PRIORITY_MAX / 3, 20);
-
-    if (tid != RT_NULL)
-        rt_thread_startup(tid);
+    if (tid != RT_NULL) rt_thread_startup(tid);
 
     return 0;
 }
-
-/*@}*/
diff --git a/bsp/stm32f7-disco/applications/startup.c b/bsp/stm32f7-disco/applications/startup.c
index 1ac917677..628a80504 100644
--- a/bsp/stm32f7-disco/applications/startup.c
+++ b/bsp/stm32f7-disco/applications/startup.c
@@ -26,6 +26,7 @@
 #include <rthw.h>
 #include <rtthread.h>
 #include "board.h"
+
 #ifdef RT_USING_EXT_SDRAM
 #include "drv_sdram.h"
 #include "sram.h"
@@ -61,8 +62,8 @@ void assert_failed(uint8_t* file, uint32_t line)
   while (1)
   {}
 }
-
 #endif
+
 /**
  * This function will startup RT-Thread RTOS.
  */
@@ -113,7 +114,7 @@ void rtthread_startup(void)
 int main(void)
 {
     /* disable interrupt first */
-    //rt_hw_interrupt_disable();
+    rt_hw_interrupt_disable();
 
     /* startup RT-Thread RTOS */
     rtthread_startup();
diff --git a/bsp/stm32f7-disco/drivers/board.c b/bsp/stm32f7-disco/drivers/board.c
index 4d5c0d616..734ecf209 100644
--- a/bsp/stm32f7-disco/drivers/board.c
+++ b/bsp/stm32f7-disco/drivers/board.c
@@ -69,16 +69,18 @@ static void SystemClock_Config(void)
     RCC_OscInitStruct.PLL.PLLM = 25;
     RCC_OscInitStruct.PLL.PLLN = 400;
     RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
-    HAL_RCC_OscConfig(&RCC_OscInitStruct);
+    RCC_OscInitStruct.PLL.PLLQ = 8;
+    
+    ret = HAL_RCC_OscConfig(&RCC_OscInitStruct);
+    if(ret != HAL_OK)
+    {
+        while(1) { ; }
+    }
 
     ret = HAL_PWREx_EnableOverDrive();
-
     if (ret != HAL_OK)
     {
-        while (1)
-        {
-            ;
-        }
+        while (1) { ; }
     }
 
     /* Select PLL as system clock source and configure the HCLK, PCLK1 and PCLK2
@@ -88,7 +90,11 @@ static void SystemClock_Config(void)
     RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
     RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV4;
     RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;
-    HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_6);
+    ret = HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_6);
+    if (ret != HAL_OK)
+    {
+        while (1) { ; }
+    }
 }
 
 /**
@@ -115,18 +121,46 @@ static void CPU_CACHE_Enable(void)
  */
 void SysTick_Handler(void)
 {
-    /* tick for HAL Library */
-    HAL_IncTick();
-
     /* enter interrupt */
     rt_interrupt_enter();
 
+    /* tick for HAL Library */
+    HAL_IncTick();
+
     rt_tick_increase();
 
     /* leave interrupt */
     rt_interrupt_leave();
 }
 
+/* re-implementat tick interface for STM32 HAL */
+HAL_StatusTypeDef HAL_InitTick(uint32_t TickPriority)
+{
+    /*Configure the SysTick to have interrupt in 1ms time basis*/
+    HAL_SYSTICK_Config(HAL_RCC_GetHCLKFreq()/RT_TICK_PER_SECOND);
+
+    /*Configure the SysTick IRQ priority */
+    HAL_NVIC_SetPriority(SysTick_IRQn, TickPriority ,0);
+
+    /* Return function status */
+    return HAL_OK;
+}
+
+void HAL_Delay(__IO uint32_t Delay)
+{
+    rt_thread_delay(Delay);
+}
+
+void HAL_SuspendTick(void)
+{
+    /* we should not suspend tick */
+}
+
+void HAL_ResumeTick(void)
+{
+    /* we should not resume tick */
+}
+
 /**
  * This function will initial STM32 board.
  */
diff --git a/bsp/stm32f7-disco/drivers/drv_led.c b/bsp/stm32f7-disco/drivers/drv_led.c
index a58c5f3b6..be86615b2 100644
--- a/bsp/stm32f7-disco/drivers/drv_led.c
+++ b/bsp/stm32f7-disco/drivers/drv_led.c
@@ -21,9 +21,22 @@
  * Date           Author       Notes
  * 2015-08-01     xiaonong     the first version
  */
-
+#include <rtthread.h>
 #include <board.h>
 
+#include "drv_led.h"
+
+static void led_thread_entry(void *parameter)
+{
+    while (1)
+    {
+        led_on();
+        rt_thread_delay(RT_TICK_PER_SECOND);
+        led_off();
+        rt_thread_delay(RT_TICK_PER_SECOND);
+    }
+}
+
 int led_hw_init(void)
 {
    GPIO_InitTypeDef GPIO_InitStruct;
@@ -39,5 +52,19 @@ int led_hw_init(void)
   HAL_GPIO_Init(GPIOI, &GPIO_InitStruct);
   return 0;
 }
+INIT_BOARD_EXPORT(led_hw_init);
 
+int led_init(void)
+{
+    rt_thread_t tid;
 
+    tid = rt_thread_create("led",
+                           led_thread_entry, RT_NULL,
+                           512, 12, 5);
+
+    if (tid != RT_NULL)
+        rt_thread_startup(tid);
+
+    return 0;
+}
+INIT_APP_EXPORT(led_init);
diff --git a/bsp/stm32f7-disco/drivers/drv_mpu.c b/bsp/stm32f7-disco/drivers/drv_mpu.c
index 284887846..4cab4d228 100644
--- a/bsp/stm32f7-disco/drivers/drv_mpu.c
+++ b/bsp/stm32f7-disco/drivers/drv_mpu.c
@@ -47,6 +47,36 @@ void mpu_init(void)
 
   HAL_MPU_ConfigRegion(&MPU_InitStruct);
 
+  /* Configure the MPU attributes as WB for SDRAM */
+  MPU_InitStruct.Enable = MPU_REGION_ENABLE;
+  MPU_InitStruct.BaseAddress = 0xC0000000;
+  MPU_InitStruct.Size = MPU_REGION_SIZE_8MB;
+  MPU_InitStruct.AccessPermission = MPU_REGION_FULL_ACCESS;
+  MPU_InitStruct.IsBufferable = MPU_ACCESS_BUFFERABLE;
+  MPU_InitStruct.IsCacheable = MPU_ACCESS_CACHEABLE;
+  MPU_InitStruct.IsShareable = MPU_ACCESS_NOT_SHAREABLE;
+  MPU_InitStruct.Number = MPU_REGION_NUMBER1;
+  MPU_InitStruct.TypeExtField = MPU_TEX_LEVEL0;
+  MPU_InitStruct.SubRegionDisable = 0x00;
+  MPU_InitStruct.DisableExec = MPU_INSTRUCTION_ACCESS_ENABLE;
+
+  HAL_MPU_ConfigRegion(&MPU_InitStruct);
+
+  /* Configure the MPU attributes as none-cache for 1MB SDRAM */
+  MPU_InitStruct.Enable = MPU_REGION_ENABLE;
+  MPU_InitStruct.BaseAddress = 0xC0100000;
+  MPU_InitStruct.Size = MPU_REGION_SIZE_1MB;
+  MPU_InitStruct.AccessPermission = MPU_REGION_FULL_ACCESS;
+  MPU_InitStruct.IsBufferable = MPU_ACCESS_NOT_BUFFERABLE;
+  MPU_InitStruct.IsCacheable = MPU_ACCESS_NOT_CACHEABLE;
+  MPU_InitStruct.IsShareable = MPU_ACCESS_NOT_SHAREABLE;
+  MPU_InitStruct.Number = MPU_REGION_NUMBER2;
+  MPU_InitStruct.TypeExtField = MPU_TEX_LEVEL0;
+  MPU_InitStruct.SubRegionDisable = 0x00;
+  MPU_InitStruct.DisableExec = MPU_INSTRUCTION_ACCESS_ENABLE;
+
+  HAL_MPU_ConfigRegion(&MPU_InitStruct);
+    
   /* Enable the MPU */
   HAL_MPU_Enable(MPU_PRIVILEGED_DEFAULT);
 }
diff --git a/bsp/stm32f7-disco/drivers/drv_sdram.c b/bsp/stm32f7-disco/drivers/drv_sdram.c
index fd61b83ae..4b58e21d0 100644
--- a/bsp/stm32f7-disco/drivers/drv_sdram.c
+++ b/bsp/stm32f7-disco/drivers/drv_sdram.c
@@ -24,12 +24,10 @@
 
 #include "drv_sdram.h"
 
-
 static SDRAM_HandleTypeDef sdramHandle;
 static FMC_SDRAM_TimingTypeDef Timing;
 static FMC_SDRAM_CommandTypeDef Command;
 
-
 /**
   * @brief  Initializes SDRAM MSP.
   * @param  hsdram: SDRAM handle
@@ -162,8 +160,11 @@ static void SDRAM_InitializationSequence(uint32_t RefreshCount)
 
   /* Step 2: Insert 100 us minimum delay */ 
   /* Inserted delay is equal to 1 ms due to systick time base unit (ms) */
-  HAL_Delay(1);
-    
+  // HAL_Delay(1);
+	/* interrupt is not enable, just to delay some time. */
+	for (tmpmrd = 0; tmpmrd < 0xfffff; tmpmrd ++)
+		;
+
   /* Step 3: Configure a PALL (precharge all) command */ 
   Command.CommandMode            = FMC_SDRAM_CMD_PALL;
   Command.CommandTarget          = FMC_SDRAM_CMD_TARGET_BANK1;
@@ -361,94 +362,3 @@ void SDRAM_DMA_IRQHandler(void)
 {
   HAL_DMA_IRQHandler(sdramHandle.hdma); 
 }
-
-
-
-#ifdef RT_USING_FINSH
-#include <finsh.h>
-int sdram_test(void)
-{
-    uint32_t i;
-    volatile uint32_t *wr_ptr;
-    volatile uint8_t *char_wr_ptr;
-    volatile uint16_t *short_wr_ptr;
-
-    /* initialize memory */
-    rt_kprintf("SDRAM初始化...\r\n");
-
-    wr_ptr = (uint32_t *)SDRAM_DEVICE_ADDR;
-    char_wr_ptr = (uint8_t *)wr_ptr;
-    /* 进行8位数据写测试前先清除数据*/
-    rt_kprintf("清除SDRAM数据...\r\n");
-    for (i = 0; i < SDRAM_DEVICE_SIZE / 4; i++)
-    {
-        *wr_ptr++ = 0x00;                      //写入0x00
-    }
-
-    /* 8 bit write */
-    rt_kprintf("写入8位数据...\r\n");
-    for (i = 0; i < SDRAM_DEVICE_SIZE / 4; i++)
-    {
-        *char_wr_ptr++ = 0x11;
-        *char_wr_ptr++ = 0x22;
-        *char_wr_ptr++ = 0x33;
-        *char_wr_ptr++ = 0x44;
-    }
-
-    /* 校验写入的数据*/
-    rt_kprintf("校验数据...\r\n");
-    wr_ptr = (uint32_t *)SDRAM_DEVICE_ADDR;
-    for (i = 0; i < SDRAM_DEVICE_SIZE / 8; i++)
-    {
-        if (*wr_ptr != 0x44332211)   /* be aware of endianess */
-        {
-            /* byte comparison failure */
-            rt_kprintf("校验失败，测试完毕!\r\n");
-            return 1;   /* fatal error */
-        }
-        wr_ptr++;
-    }
-
-    /* byte comparison succeed. */
-    rt_kprintf("继续测试16位数据写入...\r\n");
-    wr_ptr = (uint32_t *)SDRAM_DEVICE_ADDR;
-    short_wr_ptr = (uint16_t *)wr_ptr;
-
-    /* Clear content before 16 bit access test */
-    rt_kprintf("清除SDRAM中的数据...\r\n");
-    for (i = 0; i < SDRAM_DEVICE_SIZE / 4; i++)
-    {
-        *wr_ptr++ = 0;
-    }
-
-    /* 16 bit write */
-    rt_kprintf("写入16位数据...\r\n");
-    for (i = 0; i < (SDRAM_DEVICE_SIZE / 4); i++)
-    {
-        *short_wr_ptr++ = 0x5AA5;
-        *short_wr_ptr++ = 0xAA55;
-    }
-
-    /* Verifying */
-    wr_ptr = (uint32_t *)SDRAM_DEVICE_ADDR;
-
-    //wr_ptr -= SDRAM_BASE_ADDR/4;
-    for (i = 0; i < SDRAM_DEVICE_SIZE / 4; i++)
-    {
-        if (*wr_ptr != 0xAA555AA5)   /* be aware of endianess */
-        {
-            /* 16-bit half word failure */
-            rt_kprintf("校验失败，测试完毕!\r\n");
-            return 1;   /* fatal error */
-        }
-        wr_ptr++;
-    }
-
-    /* 16-bit half word comparison succeed. */
-
-    rt_kprintf("校验成功，测试完毕！\r\n");
-    return 0;
-}
-
-FINSH_FUNCTION_EXPORT(sdram_test, SDRAM read write test)
-#endif
diff --git a/bsp/stm32f7-disco/drivers/drv_usart.c b/bsp/stm32f7-disco/drivers/drv_usart.c
index 58e25ba39..907849c51 100644
--- a/bsp/stm32f7-disco/drivers/drv_usart.c
+++ b/bsp/stm32f7-disco/drivers/drv_usart.c
@@ -44,8 +44,6 @@
 #define USART1_RX_GPIO_PORT              GPIOB
 #define USART1_RX_AF                     GPIO_AF7_USART1
 
-
-
 /* STM32 uart driver */
 struct stm32_uart
 {
@@ -291,13 +289,11 @@ int stm32_hw_usart_init(void)
     serial1.config = config;
 
     /* register UART1 device */
-    rt_hw_serial_register(&serial1,
-                          "uart1",
+    rt_hw_serial_register(&serial1, "uart1",
                           RT_DEVICE_FLAG_RDWR | RT_DEVICE_FLAG_INT_RX,
                           uart);
 #endif /* RT_USING_UART1 */
 
-
     return 0;
 }
 INIT_BOARD_EXPORT(stm32_hw_usart_init);
diff --git a/bsp/stm32f7-disco/drivers/stm32f7xx_it.c b/bsp/stm32f7-disco/drivers/stm32f7xx_it.c
index aa3baef2f..899d4da11 100644
--- a/bsp/stm32f7-disco/drivers/stm32f7xx_it.c
+++ b/bsp/stm32f7-disco/drivers/stm32f7xx_it.c
@@ -69,19 +69,6 @@ void NMI_Handler(void)
 {
 }
 
-/**
-  * @brief  This function handles Memory Manage exception.
-  * @param  None
-  * @retval None
-  */
-void MemManage_Handler(void)
-{
-  /* Go to infinite loop when Memory Manage exception occurs */
-  while (1)
-  {
-  }
-}
-
 /**
   * @brief  This function handles Bus Fault exception.
   * @param  None
diff --git a/bsp/stm32f7-disco/rtconfig.h b/bsp/stm32f7-disco/rtconfig.h
index 98c2599d2..bd0aaed39 100644
--- a/bsp/stm32f7-disco/rtconfig.h
+++ b/bsp/stm32f7-disco/rtconfig.h
@@ -14,7 +14,7 @@
 // <item description="256">256</item>
 // </integer>
 #define RT_THREAD_PRIORITY_MAX	32
-// <integer name="RT_TICK_PER_SECOND" description="OS tick per second" default="100" />
+// <integer name="RT_TICK_PER_SECOND" description="OS tick per second" default="1000" />
 #define RT_TICK_PER_SECOND	1000
 // <integer name="IDLE_THREAD_STACK_SIZE" description="The stack size of idle thread" default="512" />
 #define IDLE_THREAD_STACK_SIZE	512
@@ -141,16 +141,16 @@
 // <item description="LFN with dynamic LFN working buffer on the heap">3</item>
 // </integer>
 #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	936
+// <integer name="RT_DFS_ELM_CODE_PAGE" description="OEM code page" default="437">
+#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
+// #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_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" />
-#define RT_DFS_ELM_USE_ERASE
+// #define RT_DFS_ELM_USE_ERASE
 // <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" />
@@ -160,7 +160,7 @@
 // <bool name="RT_USING_DFS_ROMFS" description="Using ROMFS" default="false" />
 //#define RT_USING_DFS_ROMFS
 // <bool name="RT_USING_DFS_NFS" description="Using NFS" default="false" />
-#define RT_USING_DFS_NFS
+// #define RT_USING_DFS_NFS
 // <string name="RT_NFS_HOST_EXPORT" description="The exported NFS host path" default="192.168.1.10:/" />
 #define RT_NFS_HOST_EXPORT	"192.168.137.1:/"
 // </section>
@@ -223,6 +223,7 @@
 // </section>
 
 // </RDTConfigurator>
+
 /* enable SDRAM */
 #define RT_USING_EXT_SDRAM
 
diff --git a/bsp/stm32f7-disco/rtconfig.py b/bsp/stm32f7-disco/rtconfig.py
index 475bdd500..91ef8db8b 100644
--- a/bsp/stm32f7-disco/rtconfig.py
+++ b/bsp/stm32f7-disco/rtconfig.py
@@ -3,10 +3,12 @@ import os
 # toolchains options
 ARCH='arm'
 CPU='cortex-m7'
-CROSS_TOOL='keil'
+CROSS_TOOL='gcc'
 
 if os.getenv('RTT_CC'):
     CROSS_TOOL = os.getenv('RTT_CC')
+if os.getenv('RTT_ROOT'):
+    RTT_ROOT = os.getenv('RTT_ROOT')
 
 # cross_tool provides the cross compiler
 # EXEC_PATH is the compiler execute path, for example, CodeSourcery, Keil MDK, IAR
@@ -23,7 +25,7 @@ elif CROSS_TOOL == 'iar':
     exit(0)
 
 if os.getenv('RTT_EXEC_PATH'):
-	EXEC_PATH = os.getenv('RTT_EXEC_PATH')
+    EXEC_PATH = os.getenv('RTT_EXEC_PATH')
 
 BUILD = 'debug'
 STM32_TYPE = 'STM32F756xx'
@@ -32,6 +34,7 @@ if PLATFORM == 'gcc':
     # toolchains
     PREFIX = 'arm-none-eabi-'
     CC = PREFIX + 'gcc'
+    CXX = PREFIX + 'g++'
     AS = PREFIX + 'gcc'
     AR = PREFIX + 'ar'
     LINK = PREFIX + 'gcc'
@@ -39,6 +42,7 @@ if PLATFORM == 'gcc':
     SIZE = PREFIX + 'size'
     OBJDUMP = PREFIX + 'objdump'
     OBJCPY = PREFIX + 'objcopy'
+    STRIP = PREFIX + 'strip'
 
     DEVICE = '  -mcpu=cortex-m7 -mthumb -mfpu=fpv4-sp-d16 -mfloat-abi=softfp -ffunction-sections -fdata-sections'
     CFLAGS = DEVICE + ' -g -Wall -DSTM32F756xx -DUSE_HAL_DRIVER -D__ASSEMBLY__ -D__FPU_USED'
@@ -52,13 +56,22 @@ if PLATFORM == 'gcc':
         CFLAGS += ' -O0 -gdwarf-2'
         AFLAGS += ' -gdwarf-2'
     else:
-        CFLAGS += ' -O2'
+        CFLAGS += ' -O2 -Os'
 
     POST_ACTION = OBJCPY + ' -O binary $TARGET rtthread.bin\n' + SIZE + ' $TARGET \n'
 
+    # module setting 
+    CXXFLAGS = ' -Woverloaded-virtual -fno-exceptions -fno-rtti '
+    M_CFLAGS = CFLAGS + ' -mlong-calls -fPIC '
+    M_CXXFLAGS = CXXFLAGS + ' -mlong-calls -fPIC'
+    M_LFLAGS = DEVICE + CXXFLAGS + ' -Wl,--gc-sections,-z,max-page-size=0x4' +\
+                                    ' -shared -fPIC -nostartfiles -static-libgcc'
+    M_POST_ACTION = STRIP + ' -R .hash $TARGET\n' + SIZE + ' $TARGET \n'
+
 elif PLATFORM == 'armcc':
     # toolchains
     CC = 'armcc'
+    CXX = 'armcc'
     AS = 'armasm'
     AR = 'armar'
     LINK = 'armlink'
@@ -78,8 +91,9 @@ elif PLATFORM == 'armcc':
         CFLAGS += ' -g -O0'
         AFLAGS += ' -g'
     else:
-        CFLAGS += ' -O2'
+        CFLAGS += ' -O2 -Otime'
 
+    CXXFLAGS = CFLAGS
     POST_ACTION = 'fromelf --bin $TARGET --output rtthread.bin \nfromelf -z $TARGET'
 
 elif PLATFORM == 'iar':
diff --git a/components/dfs/filesystems/lwip/lwip_select.c b/components/dfs/filesystems/lwip/lwip_select.c
index 7e97d3741..3477b6f1d 100644
--- a/components/dfs/filesystems/lwip/lwip_select.c
+++ b/components/dfs/filesystems/lwip/lwip_select.c
@@ -27,6 +27,8 @@
 
 #ifdef RT_USING_LWIP
 
+#include "dfs_lwip.h"
+
 int
 select(int maxfdp1, fd_set *readset, fd_set *writeset, fd_set *exceptset,
             struct timeval *timeout)
@@ -70,7 +72,7 @@ select(int maxfdp1, fd_set *readset, fd_set *writeset, fd_set *exceptset,
     if (maxfd == 0) return -EBADF;
     maxfd += 1;
     
-    result = lwip_selscan(maxfd, &sock_readset, &sock_writeset, &sock_exceptset, timeout);
+    result = lwip_select(maxfd, &sock_readset, &sock_writeset, &sock_exceptset, timeout);
     
     if (readset)   FD_ZERO(readset);
     if (writeset)  FD_ZERO(writeset);
diff --git a/libcpu/arm/cortex-m7/context_rvds.S b/libcpu/arm/cortex-m7/context_rvds.S
index fa7a1c90f..53a375678 100644
--- a/libcpu/arm/cortex-m7/context_rvds.S
+++ b/libcpu/arm/cortex-m7/context_rvds.S
@@ -221,7 +221,9 @@ rt_hw_interrupt_thread_switch PROC
 
     IMPORT rt_hw_hard_fault_exception
     EXPORT HardFault_Handler
+    EXPORT MemManage_Handler
 HardFault_Handler    PROC
+MemManage_Handler
 
     ; get current context
     MRS     r0, psp                 ; get fault thread stack pointer