diff --git a/Ubiquitous/XiZi_IIoT/resources/serial/dev_serial.c b/Ubiquitous/XiZi_IIoT/resources/serial/dev_serial.c
index 428e1c935..fcd9aeefd 100644
--- a/Ubiquitous/XiZi_IIoT/resources/serial/dev_serial.c
+++ b/Ubiquitous/XiZi_IIoT/resources/serial/dev_serial.c
@@ -154,7 +154,9 @@ 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 2d4634cb9..0c26a69a1 100644
--- a/Ubiquitous/XiZi_IIoT/tool/bootloader/ota/ota.c
+++ b/Ubiquitous/XiZi_IIoT/tool/bootloader/ota/ota.c
@@ -610,7 +610,8 @@ send_ready_again:
                     goto send_ready_again;
                 }
                 printf("start receive ota file.\n");
-                /* step2: start receive bin file */
+                /* step2: start receive bin file,first wait for 5s*/
+                PrivTaskDelay(5000);
                 ret = ota_data_recv(adapter);
                 if (0 != ret)
                 {
diff --git a/Ubiquitous/XiZi_IIoT/tool/bootloader/ota/server_tcp.c b/Ubiquitous/XiZi_IIoT/tool/bootloader/ota/server_tcp.c
index d74701723..108e9e896 100644
--- a/Ubiquitous/XiZi_IIoT/tool/bootloader/ota/server_tcp.c
+++ b/Ubiquitous/XiZi_IIoT/tool/bootloader/ota/server_tcp.c
@@ -376,6 +376,7 @@ void* server_thread(void* p)
     printf("pthread = %d\n",fd);
     sleep(5);
     ota_start_signal(fd);
+    sleep(5);
     while(1)
     {
         ret = ota_file_send(fd);