diff --git a/cap/zx297520v3/src/lynq/framework/lynq-fota-backup/lynq-fota-backup.cpp b/cap/zx297520v3/src/lynq/framework/lynq-fota-backup/lynq-fota-backup.cpp
index c2e7d1d..887d036 100755
--- a/cap/zx297520v3/src/lynq/framework/lynq-fota-backup/lynq-fota-backup.cpp
+++ b/cap/zx297520v3/src/lynq/framework/lynq-fota-backup/lynq-fota-backup.cpp
@@ -34,6 +34,8 @@
 
 #define USER_LOG_TAG "LYNQ_FOTA_BACKUP"
 
+#define SYNC_RUNNING_FLAG "/tmp/sync_running.flag"
+#define UPDATE_ACTIVE_FLAG "/tmp/update_active.flag"
 extern int lynq_sync_system();
 extern int lynq_fota_get_addr_value(char *tmp_value);
 extern int lynq_fota_set_addr_value(char        *value,int size);
@@ -192,6 +194,34 @@
 
 }
 
+static int set_sync_status(int active)
+{
+    if (active) 
+    {
+        FILE *fp = fopen(SYNC_RUNNING_FLAG, "wx");
+        if (!fp) 
+	{
+            LYERRLOG("Open sync_running_flag file failed.\n");
+            return -1;
+        }
+        fprintf(fp, "Sync started\n");
+        fclose(fp);
+        LYERRLOG("Sync: Status flag created: %s\n", SYNC_RUNNING_FLAG);
+    } 
+    else 
+    {
+        if (unlink(SYNC_RUNNING_FLAG) == -1) 
+	{
+                LYERRLOG("Sync: Failed to remove running flag");
+                return -1;
+        }
+        LYERRLOG("Sync: Status flag removed: %s\n", SYNC_RUNNING_FLAG);
+    }
+    system("sync");
+    return 0;
+}
+
+
 int main()
 {
     int ret = 0 ;
@@ -199,12 +229,25 @@
     char tmp_addr[128] = {0};
     FILE *fp = NULL;
 
+    if (access(UPDATE_ACTIVE_FLAG, F_OK) == 0) 
+    {
+        LYERRLOG("No need fota sync: Upgrade is active.\n");
+        return -1;
+    }
+
+    ret = set_sync_status(1);
+    if(ret != 0)
+    {
+	LYERRLOG("set sync status:1 error\n");
+        return -1;
+    }
     check_need_sync();
 
     fp = fopen(FOTA_FLAG_FILE,"r");
     if(fp == NULL)
     {
         LYERRLOG("No need fota sync\n");
+    	set_sync_status(0);
         return -1;
 
     }
@@ -230,6 +273,7 @@
         if(ret != 0)
         {
             LYERRLOG("Get addr failed\n");
+    	    set_sync_status(0);
             return -1;
         }
         LYINFLOG("tmp_addr is %s\n",tmp_addr);
@@ -237,18 +281,21 @@
         if(ret != 0)
         {
             LYERRLOG("Set addr failed\n");
+    	    set_sync_status(0);
             return -1;
         }
         ret = lynq_fota_nrestart();
         if(ret != 0)
         {
             LYERRLOG("Upgrade failed\n");
+    	    set_sync_status(0);
             return -1;
         }
         
     }
-   
-    return 0;
+
+    set_sync_status(0);
+    return ret;
 
 }
 DEFINE_LYNQ_LIB_LOG(LYNQ_FOTA_BACKUP)
diff --git a/cap/zx297520v3/src/lynq/lib/liblynq-qser-fota/lynq-qser-fota.cpp b/cap/zx297520v3/src/lynq/lib/liblynq-qser-fota/lynq-qser-fota.cpp
index 811e7e7..20816fb 100755
--- a/cap/zx297520v3/src/lynq/lib/liblynq-qser-fota/lynq-qser-fota.cpp
+++ b/cap/zx297520v3/src/lynq/lib/liblynq-qser-fota/lynq-qser-fota.cpp
@@ -39,6 +39,8 @@
 #define  SYSTEM_A  "34650"
 #define  SYSTEM_B  "39019"
 
+#define SYNC_RUNNING_FLAG "/tmp/sync_running.flag"
+#define UPDATE_ACTIVE_FLAG "/tmp/update_active.flag"
 
 #define BOOTABLE   "45227"
 #define UNBOOTABLE "47806"
@@ -125,11 +127,36 @@
 int lynq_set_sync_status(char *option_para);
 int  calculate_md5_sum( char *md5_sum,int md5_size);
 
+
+static int can_run_update() 
+{
+    if (access(SYNC_RUNNING_FLAG, F_OK) == 0) 
+    {
+        LYINFLOG("Update: Status=-2 (Sync is running, please try later)\n");
+        return -2;
+    }
+
+    return 0;
+}
+
+static int set_update_flag()
+{
+    FILE *fp = fopen(UPDATE_ACTIVE_FLAG, "w");
+    if (!fp) 
+    {
+        LYINFLOG("open update_active_flag file failed \n");
+        return -1;
+    }
+    fprintf(fp, "OTA update active");
+    fclose(fp);
+    system("sync");
+    return 0;
+}
 /*****************************************
 * @brief:rock_update_main
 * @param count [IN]:NA
 * @param sum [OUT]:NA
-* @return :success 0, failed -1
+* @return :success 0, failed -1, busy -2
 * @todo:NA
 * @see:NA
 * @warning:NA
@@ -146,8 +173,16 @@
     struct tm *localTime;
     double elapsed = 0;
     char md5_sum[48] = {0};
-
-    FILE *fp = NULL;
+    FILE *fp = NULL; 
+    
+    if(set_update_flag() != 0)
+    {
+    	return -1;
+    }
+    if(can_run_update() != 0)
+    {
+	return -2;
+    }
     fp = fopen(FOTA_FLAG_FILE,"w+");
     if(fp == NULL)
     {
@@ -474,7 +509,7 @@
 * @brief:lynq_fota_nrestart no reboot
 * @param count [IN]:NA
 * @param sum [OUT]:NA
-* @return :success 0, failed -1
+* @return :success 0, failed -1, busy -2
 * @todo:NA
 * @see:NA
 * @warning:NA
@@ -515,7 +550,7 @@
 * @brief:lynq_rock_main,upgrade done reboot
 * @param count [IN]:int first_run
 * @param sum [OUT]:NA
-* @return :success 0, failed -1
+* @return :success 0, failed -1, busy -2
 * @todo:NA
 * @see:NA
 * @warning:NA