diff --git a/include/SystemConfiguration.h b/include/SystemConfiguration.h
index 5503b5a..3ccccd0 100644
--- a/include/SystemConfiguration.h
+++ b/include/SystemConfiguration.h
@@ -98,7 +98,9 @@
         char SysName[32];       ///< User Name
         char SysPass[32];       ///< User Password
         char OTAURL[64];        ///< OTA URL
-        uint8_t imei[4];
+
+        char SN[11];        ///< String of serial number (decimal ID)
+        char ID[9];        ///< String of ID ( last 4 bytes of MAC)
 
         struct
         {
diff --git a/src/HTTPPrintSystem.c b/src/HTTPPrintSystem.c
index 2377278..4554ad1 100644
--- a/src/HTTPPrintSystem.c
+++ b/src/HTTPPrintSystem.c
@@ -150,16 +150,11 @@ static void HTTPPrint_ota(char *VarData, void *arg)
 
 static void HTTPPrint_serial(char *VarData, void *arg)
 {
-    char ser1[4], ser2[9];
-    GetChipId((uint8_t*) ser1);
-    BytesToStr((unsigned char*) ser1, (unsigned char*) ser2, 4);
-    snprintf(VarData, MAX_DYNVAR_LENGTH, "%s", ser2);
+    snprintf(VarData, MAX_DYNVAR_LENGTH, "%s", GetSysConf()->ID);
 }
 static void HTTPPrint_serial10(char *VarData, void *arg)
 {
-    UINT32_VAL d;
-    GetChipId((uint8_t*) d.v);
-    snprintf(VarData, MAX_DYNVAR_LENGTH, "%010u", swap(d.Val));
+    snprintf(VarData, MAX_DYNVAR_LENGTH, "%s", GetSysConf()->SN);
 }
 
 static void HTTPPrint_fver(char *VarData, void *arg)
diff --git a/src/MQTT.c b/src/MQTT.c
index 07298b9..0d35714 100644
--- a/src/MQTT.c
+++ b/src/MQTT.c
@@ -269,8 +269,7 @@ static void start_mqtt()
             mqtt_cfg.password = GetSysConf()->mqttStation[i].UserPass;
             strcpy(tmp, GetSysConf()->mqttStation[i].ClientID);
             strcat(tmp, "_");
-            int len = strlen(tmp);
-            BytesToStr((unsigned char*) &GetSysConf()->imei, (unsigned char*) &tmp[len], 4);
+            strcat(tmp, GetSysConf()->ID);
             mqtt_cfg.client_id = tmp;
             mqtt[i].is_connected = false;
             mqtt[i].mqtt_index = i;
diff --git a/src/SystemConfiguration.c b/src/SystemConfiguration.c
index 295aa8c..2e5430e 100644
--- a/src/SystemConfiguration.c
+++ b/src/SystemConfiguration.c
@@ -236,6 +236,16 @@ static void InitSysI2C(void)
 
 static void ResetSysConfig(SYS_CONFIG *Conf)
 {
+    char id[4]; char id2[9];
+    GetChipId((uint8_t*) id);
+    BytesToStr((unsigned char*) id, (unsigned char*) id2, 4);
+    id2[8] = 0x00;
+    memcpy(Conf->ID, id2, 9);
+
+    UINT32_VAL d;
+    GetChipId((uint8_t*) d.v);
+    snprintf(Conf->SN, 11, "%010u", swap(d.Val));
+
     memcpy(Conf->NetBIOSName, CONFIG_WEBGUIAPP_HOSTNAME, sizeof(CONFIG_WEBGUIAPP_HOSTNAME));
     memcpy(Conf->SysName, CONFIG_WEBGUIAPP_USERNAME, sizeof(CONFIG_WEBGUIAPP_USERNAME));
     memcpy(Conf->SysPass, CONFIG_WEBGUIAPP_USERPASS, sizeof(CONFIG_WEBGUIAPP_USERPASS));
@@ -244,15 +254,9 @@ static void ResetSysConfig(SYS_CONFIG *Conf)
     memcpy(Conf->OTAURL, SYSTEM_DEFAULT_OTAURL, sizeof(SYSTEM_DEFAULT_OTAURL));
 #if CONFIG_WEBGUIAPP_WIFI_ENABLE
     Conf->wifiSettings.Flags1.bIsWiFiEnabled = CONFIG_WEBGUIAPP_WIFI_ON;
-
-    char id[4];
-    char id2[9];
-    GetChipId((uint8_t*) id);
-    BytesToStr((unsigned char*) id, (unsigned char*) id2, 4);
-    id2[8] = 0x00;
     memcpy(Conf->wifiSettings.ApSSID, CONFIG_WEBGUIAPP_WIFI_SSID_AP, sizeof(CONFIG_WEBGUIAPP_WIFI_SSID_AP));
     strcat(Conf->wifiSettings.ApSSID, "_");
-    strcat(Conf->wifiSettings.ApSSID, id2);
+    strcat(Conf->wifiSettings.ApSSID, Conf->ID);
 
     esp_netif_str_to_ip4(CONFIG_WEBGUIAPP_WIFI_IP_STA, (esp_ip4_addr_t*) &Conf->wifiSettings.InfIPAddr);
     esp_netif_str_to_ip4(CONFIG_WEBGUIAPP_WIFI_MASK_STA, (esp_ip4_addr_t*) &Conf->wifiSettings.InfMask);
@@ -307,8 +311,6 @@ static void ResetSysConfig(SYS_CONFIG *Conf)
     memcpy(Conf->mqttStation[1].UserPass, CONFIG_WEBGUIAPP_MQTT_PASSWORD, sizeof(CONFIG_WEBGUIAPP_MQTT_PASSWORD));
 #endif
 #endif
-    GetChipId(Conf->imei);
-
     memcpy(Conf->sntpClient.SntpServerAdr, DEFAULT_SNTP_SERVERNAME, sizeof(DEFAULT_SNTP_SERVERNAME));
     Conf->sntpClient.Flags1.bIsEthEnabled = DEFAULT_SNTP_ETH_IS_ENABLED;
     Conf->sntpClient.Flags1.bIsWifiEnabled = DEFAULT_SNTP_WIFI_IS_ENABLED;