diff --git a/src/python/devtest/os/conn/Serial.py b/src/python/devtest/os/conn/Serial.py
index 92e93f1..2514921 100644
--- a/src/python/devtest/os/conn/Serial.py
+++ b/src/python/devtest/os/conn/Serial.py
@@ -118,6 +118,7 @@ class Serial(Connection): # export
             self._parent = parent
             self._rd_stream = None
             self._wr_stream = None
+            self._protocol = None
             self._fd = None
             self._stream_reader = None
             self._stream_writer = None
@@ -259,7 +260,8 @@ class Serial(Connection): # export
                     #transp, proto = await self.pair.env.eloop.connect_read_pipe(Fifos.Protocol, self._rd_stream)
                     #self._stream_reader = asyncio.streams.StreamReader(transp, proto, None, loop)
                     self._stream_reader = asyncio.StreamReader(limit=limit, loop=loop)
-                    await loop.connect_read_pipe(lambda: asyncio.StreamReaderProtocol(self._stream_reader, loop=loop), self._rd_stream)
+                    self._protocol = asyncio.StreamReaderProtocol(self._stream_reader, loop=loop)
+                    await loop.connect_read_pipe(lambda: self._protocol, self._rd_stream)
             except:
                 await self.close()
                 raise
@@ -276,6 +278,7 @@ class Serial(Connection): # export
                 #self._rd_stream.close()
                 #await self._rd_stream.wait_closed()
                 self._rd_stream = None
+            self._protocol = None
             self._stream_writer = None
             self._stream_reader = None
             self._fd = None