diff --git a/tools/bridge_server.py b/tools/bridge_server.py
index ba85228..9fb550e 100644
--- a/tools/bridge_server.py
+++ b/tools/bridge_server.py
@@ -27,7 +27,7 @@ import platform
 import sys
 
 PROTOCOL_VERSION = 1
-SERVER_BUILD = 6  # 2026-07-29: read 增加 dis_model/dis_fw/spota_mem_info/spota_status_ro（SUOTA 审慎测试基线）
+SERVER_BUILD = 7  # 2026-07-29: OTA 分阶段事件(mem_dev/gpio_map/block_sent/status)+写超时，定位卡点
 
 EPD_SERVICE_UUID = "13187b10-eba9-a3ba-044e-83d3217d9a38"
 EPD_CHAR_UUID = "4b646063-6264-f3a7-8941-e65356ea82fe"
@@ -163,23 +163,29 @@ class BleSession:
         payload = image + bytes([acc])
         blocks = [payload[i:i + BLOCK_SIZE] for i in range(0, len(payload), BLOCK_SIZE)]
 
+        async def w(char, data, to=15.0):
+            await asyncio.wait_for(
+                self.client.write_gatt_char(char, data, response=True), to)
+
         await self.client.start_notify(SPOTA_SERV_STATUS_UUID, _on_status)
-        events = []
         try:
-            await self.client.write_gatt_char(SPOTA_MEM_DEV_UUID, MEM_DEV_SPI_FLASH, response=True)
-            await self.client.write_gatt_char(SPOTA_GPIO_MAP_UUID, GPIO_MAP_DEFAULT, response=True)
+            await w(SPOTA_MEM_DEV_UUID, MEM_DEV_SPI_FLASH)
+            yield {"event": "ota_stage", "stage": "mem_dev_ok"}
+            await w(SPOTA_GPIO_MAP_UUID, GPIO_MAP_DEFAULT)
+            yield {"event": "ota_stage", "stage": "gpio_map_ok"}
             for idx, block in enumerate(blocks, 1):
-                await self.client.write_gatt_char(SPOTA_PATCH_LEN_UUID,
-                                                  len(block).to_bytes(2, "little"), response=True)
+                await w(SPOTA_PATCH_LEN_UUID, len(block).to_bytes(2, "little"))
                 for i in range(0, len(block), WRITE_CHUNK):
                     await self.client.write_gatt_char(SPOTA_PATCH_DATA_UUID,
                                                       block[i:i + WRITE_CHUNK], response=False)
+                yield {"event": "ota_block_sent", "block": idx, "total": len(blocks)}
                 await wait_ok(f"块 {idx}/{len(blocks)}")
-                events.append({"block": idx, "total": len(blocks)})
                 yield {"event": "ota_progress", "block": idx, "total": len(blocks)}
-            await self.client.write_gatt_char(SPOTA_MEM_DEV_UUID, END_SIGNAL, response=True)
+            await w(SPOTA_MEM_DEV_UUID, END_SIGNAL)
+            yield {"event": "ota_stage", "stage": "end_signal_ok"}
             await wait_ok("镜像校验")
-            await self.client.write_gatt_char(SPOTA_MEM_DEV_UUID, REBOOT_SIGNAL, response=True)
+            await w(SPOTA_MEM_DEV_UUID, REBOOT_SIGNAL)
+            yield {"event": "ota_stage", "stage": "reboot_sent"}
         finally:
             try:
                 await self.client.stop_notify(SPOTA_SERV_STATUS_UUID)