diff --git a/vd960DBN/BLE/OnlyUpdateApp_Peripheral/APP/iot_mqtt_srv.c b/vd960DBN/BLE/OnlyUpdateApp_Peripheral/APP/iot_mqtt_srv.c
index 359f034..05c91fa 100644
--- a/vd960DBN/BLE/OnlyUpdateApp_Peripheral/APP/iot_mqtt_srv.c
+++ b/vd960DBN/BLE/OnlyUpdateApp_Peripheral/APP/iot_mqtt_srv.c
@@ -351,19 +351,32 @@ static int iot_mqtt_send(const uint8_t *buf, uint16_t len) {
         uint32_t slen = len - total_sent;
         uint8_t ret = WCHNET_SocketSend(g_iot_socket, (uint8_t *)(buf + total_sent), &slen);
         total_sent += (uint16_t)slen;
-        if (slen == 0 || ret != WCHNET_ERR_SUCCESS || ++retries > 10) {
-            _iot_send_fail_cnt++;
-            PRINT("IOT: SocketSend FAIL#%d ret=0x%02X sent=%u/%u\n",
-                  _iot_send_fail_cnt, ret, total_sent, len);
-            if (_iot_send_fail_cnt >= 3) {
-                PRINT("IOT: SocketSend 3 consecutive failures, forcing reconnect\n");
-                WCHNET_SocketClose(g_iot_socket, TCP_CLOSE_NORMAL);
-                g_iot_socket = 0xFF;
-                g_iot_state = IOT_STATE_DISCONNECTED;
-                _iot_send_fail_cnt = 0;
-                _iot_reconnect_deadline = mstick() + 3000;  // 3s 后重连, 让 WCHNET 清旧 socket
+        if (slen == 0 || ret != WCHNET_ERR_SUCCESS) {
+            /* 0x11 = WCHNET_ERR_MEM: 瞬时发送缓冲不足 (WCHNET_NUM_TCP_SEG=2 极小,
+               重传队列占用即无缓冲)。200ms 退避重试等 WCHNET 释放 SEG —
+               不要立即断连: 断连重连会让 WCHNET socket 表更乱
+               (SocketCreat ISCONN 死循环, 2026-08-20 现场) */
+            if (ret == WCHNET_ERR_MEM && retries < 10) {
+                uint32_t w = mstick();
+                while ((mstick() - w) < 200) { }   /* 退避 (IWDG 4s 内安全) */
             }
-            return -1;
+            retries++;
+            if (retries > 10) {
+                _iot_send_fail_cnt++;
+                PRINT("IOT: SocketSend FAIL#%d ret=0x%02X sent=%u/%u\n",
+                      _iot_send_fail_cnt, ret, total_sent, len);
+                if (_iot_send_fail_cnt >= 3) {
+                    PRINT("IOT: SocketSend 3 consecutive failures, forcing reconnect\n");
+                    WCHNET_SocketClose(g_iot_socket, TCP_CLOSE_NORMAL);
+                    g_iot_socket = 0xFF;
+                    SocketId_TCP = 0xFF;   /* 防重连 SocketCreat 沿用旧 id (2026-08-20) */
+                    g_iot_state = IOT_STATE_DISCONNECTED;
+                    _iot_send_fail_cnt = 0;
+                    _iot_reconnect_deadline = mstick() + 3000;  // 3s 后重连, 让 WCHNET 清旧 socket
+                }
+                return -1;
+            }
+            continue;   /* 重试 (MEM 已退避 200ms, 其他错误立即重试) */
         }
     }
     _iot_send_fail_cnt = 0;  // 成功一次就清零
diff --git a/vd960DBN/BLE/OnlyUpdateApp_Peripheral/APP/net_srv.c b/vd960DBN/BLE/OnlyUpdateApp_Peripheral/APP/net_srv.c
index 3acfb03..5e6cb90 100644
--- a/vd960DBN/BLE/OnlyUpdateApp_Peripheral/APP/net_srv.c
+++ b/vd960DBN/BLE/OnlyUpdateApp_Peripheral/APP/net_srv.c
@@ -346,6 +346,13 @@ void WCHNET_CreateTcpMqttSocket(void)
     {  
         PRINT("WCHNET_MQTT_SocketCreate %d,desIP:%d.%d.%d.%d, des_port:%d, srcport:%d\r\n", SocketId_TCP, RemoteIP[0],RemoteIP[1],RemoteIP[2],RemoteIP[3], iot_net_info.mqtt_port, TmpSocketInf.SourPort);
     }
+    if (i != WCHNET_ERR_SUCCESS) {
+        /* 2026-08-20: SocketCreat 失败 (0x1D ISCONN 等, 旧 socket 未清干净)
+           置无效并返回, 由上层退避重试 — 继续 Connect 只会等超时死循环 */
+        PRINT("MQTT: SocketCreat failed 0x%02X, abort connect\r\n", i);
+        SocketId_TCP = 0xFF;
+        return;
+    }
     mStopIfError(i);
     i = WCHNET_SocketConnect(SocketId_TCP);                        //make a TCP connection
     if(i == WCHNET_ERR_SUCCESS)
diff --git a/vd960DBN/docs/devlog.md b/vd960DBN/docs/devlog.md
index ae90aa9..59f6822 100644
--- a/vd960DBN/docs/devlog.md
+++ b/vd960DBN/docs/devlog.md
@@ -4,6 +4,33 @@
 >
 > 项目定位: DLD960 通信板 — BLE 配网、TCP JSON 协议服务、Loop MCU 串口桥接
 
+## 2026-08-20 — 联网 SocketSend 0x11 死循环修复：发送退避 + SocketCreat 失败中止
+
+### 现象（板级）
+
+收 report_config 后 loop_data（606B）发送失败：`SocketSend FAIL ret=0x11 sent=0/606` → 立即重试 10 次无效 → 3 次强制断连 → 重连 SocketCreat 返回 **0x1D(ISCONN)** + Connect 0x17(CLSD) → TCP connect timeout 死循环，永久失联。
+
+### 根因
+
+1. **WCHNET_NUM_TCP_SEG = WCHNET_NUM_TCP×2 = 2**（RAM 瘦身改小）：TCP 发送段缓冲仅 2 个，重传队列占用即无缓冲 → 606B 发送 `WCHNET_ERR_MEM(0x11)`
+2. **iot_mqtt_send 失败处理过激**：0x11 是瞬时（SEG 被占），却立即重试 10 次（无退避，WCHNET 没时间释放）+ 3 次就强制断连
+3. **重连缺陷**：`WCHNET_CreateTcpMqttSocket` 里 SocketCreat 失败（0x1D ISCONN，旧 socket 未清干净）后**仍继续 Connect**（mStopIfError 只打印不中止）→ 无效 socket 等超时 → 死循环；且强制重连时 `SocketId_TCP` 未置 0xFF，SocketCreat 沿用旧 id
+
+### 修复
+
+| 位置 | 改动 |
+|------|------|
+| `iot_mqtt_srv.c` iot_mqtt_send | 0x11 时 **200ms 退避重试**（等 WCHNET 释放 SEG，最多 10 次×200ms≈2s），不立即断连；非 MEM 错误立即重试 |
+| `iot_mqtt_srv.c` 强制重连 | 补 `SocketId_TCP = 0xFF`（防 SocketCreat 沿用旧 id） |
+| `net_srv.c` WCHNET_CreateTcpMqttSocket | SocketCreat 失败 → 打印 + `SocketId_TCP=0xFF` + **return 不 Connect**，由上层指数退避重试 |
+
+### 验证
+
+- 语法 0 错误
+- **待板级确认**：重发场景（瞬时 0x11）应自动恢复不断连；真断连重连失败应退避而非死循环
+
+---
+
 ## 2026-08-20 — OTA 下载失败修复：hex 提取不兼容 json.dumps 空格（单片 CRC 全错）
 
 ### 现象（板级）