diff --git a/Ubiquitous/XiZi_IIoT/resources/serial/dev_serial.c b/Ubiquitous/XiZi_IIoT/resources/serial/dev_serial.c
index fcd9aeefd..428e1c935 100644
--- a/Ubiquitous/XiZi_IIoT/resources/serial/dev_serial.c
+++ b/Ubiquitous/XiZi_IIoT/resources/serial/dev_serial.c
@@ -154,9 +154,7 @@ static inline int SerialDevIntRead(struct SerialHardwareDevice *serial_dev, stru
 
         CriticalAreaUnLock(lock);
 
-#ifndef TOOL_USING_OTA
         MdelayKTask(20);
-#endif       
 
         *read_data = get_char;
         read_data++; 
diff --git a/Ubiquitous/XiZi_IIoT/tool/bootloader/ota/ota.c b/Ubiquitous/XiZi_IIoT/tool/bootloader/ota/ota.c
index 56fcbc74f..1e83b0a36 100644
--- a/Ubiquitous/XiZi_IIoT/tool/bootloader/ota/ota.c
+++ b/Ubiquitous/XiZi_IIoT/tool/bootloader/ota/ota.c
@@ -33,13 +33,21 @@
  * Private Function Prototypes
  ****************************************************************************/
 static uint32_t calculate_crc32(uint32_t addr, uint32_t len);
+static uint16_t calculate_crc16(uint8_t * data, uint32_t len);
 static void UpdateNewApplication(void);
 static void InitialVersion(void);
 static void BackupVersion(void);
 static void BootLoaderJumpApp(void);
 static status_t UpdateOTAFlag(ota_info_t *ptr);
+static void app_ota_by_iap(void);
 static void Update(void);
 
+#ifdef CONNECTION_ADAPTER_4G
+static void get_start_signal(struct Adapter* adapter);
+static int ota_data_recv(struct Adapter* adapter);
+static void app_ota_by_4g(void);
+#endif
+
 /****************************************************************************
  * Private Data
  ****************************************************************************/
@@ -60,6 +68,7 @@ static const mcuboot_t mcuboot =
     mcuboot_delay
 };
 
+
 static const uint32_t crc32tab[] = {
     0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,
     0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91,
@@ -142,6 +151,7 @@ static uint16_t calculate_crc16(uint8_t * data, uint32_t len)
     return reg_crc;
 }
 
+
 /*******************************************************************************
 * 函 数 名: UpdateNewApplication
 * 功能描述: 在bootloader里进行调用,根据Flash中Flag分区中的信息决定是否进行版本更新
@@ -255,6 +265,7 @@ static void InitialVersion(void)
     }
 }
 
+
 /*******************************************************************************
 * 函 数 名: BackupVersion
 * 功能描述: 版本回退函数,如果升级的APP存在bug导致无法跳转需调用此函数进行版本回退
@@ -396,13 +407,14 @@ void app_clear_jumpflag(void)
     mcuboot.flash_deinit();
 }
 
+
 /*******************************************************************************
 * 函 数 名: Update
 * 功能描述: 根据实际情况进行初始化版本的烧录或者新版本的升级
 * 形    参: 无
 * 返 回 值: 无
 *******************************************************************************/
-void Update(void)
+static void Update(void)
 {
     ota_info_t ota_info;
     mcuboot.flash_init();
@@ -420,6 +432,7 @@ void Update(void)
     mcuboot.flash_deinit();
 }
 
+
 /*******************************************************************************
 * 函 数 名: ota_entry
 * 功能描述: bootloader的入口函数
@@ -667,7 +680,7 @@ try_again:
 * 形    参: adapter:Adapter指针,指向注册的4G设备
 * 返 回 值: 0:传输成功,-1:传输失败
 *******************************************************************************/
-void app_ota_by_4g(void)
+static void app_ota_by_4g(void)
 {
     struct ota_data recv_msg;
     char reply[16] = {0};
diff --git a/Ubiquitous/XiZi_IIoT/tool/bootloader/ota/server_tcp.c b/Ubiquitous/XiZi_IIoT/tool/bootloader/ota/server_tcp.c
index 08353e6b7..88871782e 100644
--- a/Ubiquitous/XiZi_IIoT/tool/bootloader/ota/server_tcp.c
+++ b/Ubiquitous/XiZi_IIoT/tool/bootloader/ota/server_tcp.c
@@ -254,6 +254,7 @@ int ota_file_send(int fd)
     if(NULL == file_fd)
     {
         printf("open file failed.\n");
+        fclose(file_fd);
         return -1;
     }
     fseek(file_fd, 0, SEEK_SET);
@@ -266,7 +267,7 @@ int ota_file_send(int fd)
 
         data.header.frame_flag = 0x5A5A;
         length = fread(data.frame.frame_data, 1, LENGTH, file_fd);
-        if(length > 0) 
+        if(length == LENGTH) 
         {
             printf("read %d bytes\n",length);
             data.frame.frame_id = frame_cnt;
@@ -274,6 +275,29 @@ int ota_file_send(int fd)
             data.frame.crc = calculate_crc16(data.frame.frame_data, length);
             file_length += length;
         }
+        else if(length > 0 && length < LENGTH)
+        {
+             if(ferror(file_fd)) 
+             {
+                printf("read %s file error!\n", basename(BIN_PATH));
+                ret = -1;
+                break;
+             }
+             else
+             {
+                printf("read %d bytes\n",length);
+                data.frame.frame_id = frame_cnt;
+                data.frame.frame_len = length;
+                data.frame.crc = calculate_crc16(data.frame.frame_data, length);
+                file_length += length;
+             }
+        }
+        //fread返回值为0,此时是个空包,不需要再发送了否则是冗余数据
+        else
+        {
+            printf("read %s file done!\n", basename(BIN_PATH));
+            break;
+        }
 
 send_again:
         printf("send frame[%d] to client %d.\n", frame_cnt, fd);
@@ -303,7 +327,7 @@ recv_again:
         else if(0 == strncmp(buf, "ok", length))
         {
             printf("receive buf[%s] length %d from client %d.\n", buf, length, fd);
-            try_times = 10;
+            try_times = 5;
             printf("send to client %d frame[%d] data send done.\n",fd, frame_cnt);
             frame_cnt++;
             continue;
@@ -319,7 +343,7 @@ recv_again:
             } 
             else
             {
-                printf("send to client %d frame[%d] 10 times failed.\n",fd, frame_cnt);
+                printf("send to client %d frame[%d] 5 times failed.\n",fd, frame_cnt);
                 ret = -1;
                 break;
             }