diff --git a/vd960DBN/BLE/OnlyUpdateApp_Peripheral/APP/iot_mqtt_srv.c b/vd960DBN/BLE/OnlyUpdateApp_Peripheral/APP/iot_mqtt_srv.c
index 5ac1b67..387824b 100644
--- a/vd960DBN/BLE/OnlyUpdateApp_Peripheral/APP/iot_mqtt_srv.c
+++ b/vd960DBN/BLE/OnlyUpdateApp_Peripheral/APP/iot_mqtt_srv.c
@@ -77,10 +77,12 @@ static int iot_mqtt_send(const uint8_t *buf, uint16_t len) {
 
 /* 发送 MQTT CONNECT */
 static int iot_mqtt_send_connect(void) {
-    MQTTPacket_connectData opts = MQTTPacket_connectData_initializer;
-    uint8_t buf[256];
+    static MQTTPacket_connectData opts;  // static: 避免 85字节栈开销
+    static uint8_t buf[256];             // static: 避免 256字节栈开销
     int len;
 
+    opts = MQTTPacket_connectData_initializer;
+
     opts.MQTTVersion = 4;   // MQTT 3.1.1
     opts.keepAliveInterval = IOT_MQTT_KEEPALIVE_SEC;
     opts.cleansession = 1;
@@ -112,7 +114,7 @@ static int iot_mqtt_send_connect(void) {
 
 /* 发送 MQTT SUBSCRIBE */
 static int iot_mqtt_send_subscribe(void) {
-    uint8_t buf[256];
+    static uint8_t buf[256];   // static: 避免栈溢出
     int len;
     char topic[IOT_MQTT_TOPIC_MAX_LEN];
     MQTTString topics[3];
@@ -142,7 +144,7 @@ static int iot_mqtt_send_subscribe(void) {
 /* 发送 MQTT PUBLISH */
 static int iot_mqtt_publish(const char *topic, const char *payload,
                              uint16_t payload_len, uint8_t qos) {
-    uint8_t buf[IOT_MQTT_SEND_BUF_LEN];
+    static uint8_t buf[IOT_MQTT_SEND_BUF_LEN];  // static: 避免 2KB 栈溢出
     int len;
     MQTTString mqtt_topic = MQTTString_initializer;
     mqtt_topic.cstring = (char *)topic;