diff --git a/prj.conf b/prj.conf
index caf22e6..f026f4c 100644
--- a/prj.conf
+++ b/prj.conf
@@ -5,23 +5,28 @@ CONFIG_BT_DEVICE_NAME="GML670_System"
 CONFIG_BT_MAX_CONN=1
 CONFIG_BT_NUS=y
 
-# 借鉴 Kiwii: 禁用 NUS 安全限制，提高连接成功率
-CONFIG_BT_NUS_SECURITY_ENABLED=n
+# DLE + PHY
+CONFIG_BT_BUF_ACL_RX_SIZE=251
+CONFIG_BT_BUF_ACL_TX_SIZE=251
+CONFIG_BT_DATA_LEN_UPDATE=y
+CONFIG_BT_USER_DATA_LEN_UPDATE=y
+CONFIG_BT_AUTO_DATA_LEN_UPDATE=y
+CONFIG_BT_L2CAP_TX_MTU=247
+CONFIG_BT_PHY_UPDATE=y
+CONFIG_BT_USER_PHY_UPDATE=y
+CONFIG_BT_AUTO_PHY_UPDATE=y
 
-# SMP 配对与绑定
-CONFIG_BT_SMP=y
-CONFIG_BT_SETTINGS=y
-CONFIG_BT_KEYS_OVERWRITE_OLDEST=y
+# 缓冲区
+CONFIG_BT_BUF_ACL_TX_COUNT=3
+CONFIG_BT_L2CAP_TX_BUF_COUNT=6
+
+# 存储
 CONFIG_FLASH=y
 CONFIG_FLASH_MAP=y
 CONFIG_NVS=y
 CONFIG_SETTINGS=y
 CONFIG_SETTINGS_NVS=y
 
-# 借鉴 Kiwii: 优化缓冲区 (匹配硬件)
-CONFIG_BT_BUF_ACL_TX_COUNT=3
-CONFIG_BT_L2CAP_TX_BUF_COUNT=3
-
 # 硬件驱动
 CONFIG_SPI=y
 CONFIG_GPIO=y
@@ -34,8 +39,11 @@ CONFIG_SERIAL=n
 CONFIG_LOG=y
 CONFIG_USE_SEGGER_RTT=y
 CONFIG_LOG_BACKEND_RTT=y
+CONFIG_LOG_BACKEND_RTT_MODE_DROP=y
 CONFIG_LOG_BACKEND_UART=n
-CONFIG_LOG_MODE_IMMEDIATE=y
+CONFIG_LOG_MODE_DEFERRED=y
+CONFIG_LOG_BUFFER_SIZE=4096
+CONFIG_SEGGER_RTT_BUFFER_SIZE_UP=4096
 CONFIG_MAIN_STACK_SIZE=4096
 
 CONFIG_CRC=y
diff --git a/src/ble_transport.c b/src/ble_transport.c
index bc22dbc..e8c96cb 100644
--- a/src/ble_transport.c
+++ b/src/ble_transport.c
@@ -62,6 +62,7 @@ static void disconnected(struct bt_conn *conn, uint8_t reason) {
 /** @brief NUS 通知使能状态回调。 */
 static void nus_send_enabled(enum bt_nus_send_status status) {
     nus_notification_enabled = (status == BT_NUS_SEND_STATUS_ENABLED);
+    LOG_INF("NUS send_enabled: status=%d, enabled=%d", status, nus_notification_enabled);
 }
 
 /**
@@ -106,10 +107,19 @@ void ble_transport_adv_start(void) {
 }
 
 void ble_transport_send(const uint8_t *data, uint16_t len) {
+    static bool first_send_logged = false;
+
     if (!nus_notification_enabled || !current_conn) return;
 
     for (int i = 0; i < 3; i++) {
-        if (bt_nus_send(current_conn, data, len) == 0) return;
+        int err = bt_nus_send(current_conn, data, len);
+        if (err == 0) {
+            if (!first_send_logged) {
+                LOG_INF("First NUS send OK (len=%u)", len);
+                first_send_logged = true;
+            }
+            return;
+        }
         k_usleep(500);
     }
     LOG_WRN("NUS send failed after retries (len=%u)", len);
diff --git a/sysbuild.cmake b/sysbuild.cmake
new file mode 100644
index 0000000..3448781
--- /dev/null
+++ b/sysbuild.cmake
@@ -0,0 +1,6 @@
+# 用绝对路径将 hci_ipc overlay 传给网络核，
+# 避免 sysbuild 在 SDK 源码目录下解析相对路径而找不到文件。
+set(hci_ipc_EXTRA_CONF_FILE
+    ${CMAKE_CURRENT_LIST_DIR}/sysbuild/hci_ipc.conf
+    CACHE INTERNAL "" FORCE
+)
diff --git a/sysbuild.conf b/sysbuild.conf
new file mode 100644
index 0000000..75e7998
--- /dev/null
+++ b/sysbuild.conf
@@ -0,0 +1,2 @@
+# 让 sysbuild 自动构建 hci_ipc 网络核固件，west flash 一次刷两个核
+SB_CONFIG_NETCORE_HCI_IPC=y
diff --git a/sysbuild/hci_ipc.conf b/sysbuild/hci_ipc.conf
new file mode 100644
index 0000000..9a7a215
--- /dev/null
+++ b/sysbuild/hci_ipc.conf
@@ -0,0 +1,9 @@
+# 网络核 hci_ipc overlay: 开启 DLE 251B，解除链路层分片瓶颈
+
+# DLE 依赖链: DATA_LEN_UPDATE -> BT_CTLR_DATA_LENGTH -> DATA_LENGTH_MAX
+CONFIG_BT_DATA_LEN_UPDATE=y
+CONFIG_BT_CTLR_DATA_LENGTH_MAX=251
+
+# 控制器 ACL 缓冲区必须能容纳 251B 的 LL PDU
+CONFIG_BT_BUF_ACL_RX_SIZE=251
+CONFIG_BT_BUF_ACL_TX_SIZE=251