diff --git a/module/device/connection.py b/module/device/connection.py
index ecbf772cc..16495887a 100644
--- a/module/device/connection.py
+++ b/module/device/connection.py
@@ -112,7 +112,7 @@ class Connection(ConnectionAttr):
             self.detect_device()
 
         # Connect
-        self.adb_connect(self.serial)
+        self.adb_connect()
         logger.attr('AdbDevice', self.adb)
 
         # Package
@@ -610,7 +610,7 @@ class Connection(ConnectionAttr):
         return self.adb_command(cmd)
 
     @Config.when(DEVICE_OVER_HTTP=False)
-    def adb_connect(self, serial):
+    def adb_connect(self):
         """
         Connect to a serial, try 3 times at max.
         If there's an old ADB server running while Alas is using a newer one, which happens on Chinese emulators,
@@ -626,7 +626,9 @@ class Connection(ConnectionAttr):
         for device in self.list_device():
             if device.status == 'offline':
                 logger.warning(f'Device {device.serial} is offline, disconnect it before connecting')
-                self.adb_disconnect(device.serial)
+                msg = self.adb_client.disconnect(device.serial)
+                if msg:
+                    logger.info(msg)
             elif device.status == 'unauthorized':
                 logger.error(f'Device {device.serial} is unauthorized, please accept ADB debugging on your device')
             elif device.status == 'device':
@@ -635,45 +637,58 @@ class Connection(ConnectionAttr):
                 logger.warning(f'Device {device.serial} is is having a unknown status: {device.status}')
 
         # Skip for emulator-5554
-        if 'emulator-' in serial:
-            logger.info(f'"{serial}" is a `emulator-*` serial, skip adb connect')
+        if 'emulator-' in self.serial:
+            logger.info(f'"{self.serial}" is a `emulator-*` serial, skip adb connect')
             return True
-        if re.match(r'^[a-zA-Z0-9]+$', serial):
-            logger.info(f'"{serial}" seems to be a Android serial, skip adb connect')
+        if re.match(r'^[a-zA-Z0-9]+$', self.serial):
+            logger.info(f'"{self.serial}" seems to be a Android serial, skip adb connect')
             return True
 
         # Try to connect
         for _ in range(3):
-            msg = self.adb_client.connect(serial)
+            msg = self.adb_client.connect(self.serial)
             logger.info(msg)
+            # Connected to 127.0.0.1:59865
+            # Already connected to 127.0.0.1:59865
             if 'connected' in msg:
-                # Connected to 127.0.0.1:59865
-                # Already connected to 127.0.0.1:59865
                 return True
+            # bad port number '598265' in '127.0.0.1:598265'
             elif 'bad port' in msg:
-                # bad port number '598265' in '127.0.0.1:598265'
-                logger.error(msg)
                 possible_reasons('Serial incorrect, might be a typo')
                 raise RequestHumanTakeover
+            # cannot connect to 127.0.0.1:55555:
+            # No connection could be made because the target machine actively refused it. (10061)
             elif '(10061)' in msg:
-                # cannot connect to 127.0.0.1:55555:
-                # No connection could be made because the target machine actively refused it. (10061)
-                logger.info(msg)
+                # MuMu12 may switch serial if port is occupied
+                # Brute force connect nearby ports to handle serial switches
+                if self.is_mumu12_family:
+                    before = self.serial
+                    for port_offset in [1, -1, 2, -2]:
+                        port = self.port + port_offset
+                        serial = self.serial.replace(str(self.port), str(port))
+                        msg = self.adb_client.connect(serial)
+                        logger.info(msg)
+                        if 'connected' in msg:
+                            break
+                    self.detect_device()
+                    if self.serial != before:
+                        return True
+                # No such device
                 logger.warning('No such device exists, please restart the emulator or set a correct serial')
                 raise EmulatorNotRunningError
 
         # Failed to connect
-        logger.warning(f'Failed to connect {serial} after 3 trial, assume connected')
+        logger.warning(f'Failed to connect {self.serial} after 3 trial, assume connected')
         self.detect_device()
         return False
 
     @Config.when(DEVICE_OVER_HTTP=True)
-    def adb_connect(self, serial):
+    def adb_connect(self):
         # No adb connect if over http
         return True
 
-    def adb_disconnect(self, serial):
-        msg = self.adb_client.disconnect(serial)
+    def adb_disconnect(self):
+        msg = self.adb_client.disconnect(self.serial)
         if msg:
             logger.info(msg)
 
@@ -703,11 +718,11 @@ class Connection(ConnectionAttr):
             # Restart Adb
             self.adb_restart()
             # Connect to device
-            self.adb_connect(self.serial)
+            self.adb_connect()
             self.detect_device()
         else:
-            self.adb_disconnect(self.serial)
-            self.adb_connect(self.serial)
+            self.adb_disconnect()
+            self.adb_connect()
             self.detect_device()
 
     @Config.when(DEVICE_OVER_HTTP=True)
@@ -982,7 +997,7 @@ class Connection(ConnectionAttr):
                 for device in available.select(may_mumu12_family=True):
                     if -2 <= device.port - self.port <= 2:
                         # Port switched
-                        logger.info(f'MuMu12 port switches from {self.serial} to {device.serial}')
+                        logger.info(f'MuMu12 serial switched {self.serial} -> {device.serial}')
                         del_cached_property(self, 'port')
                         del_cached_property(self, 'is_mumu12_family')
                         del_cached_property(self, 'is_mumu_family')