diff --git a/tests/test_websockifyserver.py b/tests/test_websockifyserver.py
index 4f46cb19..79d1b258 100644
--- a/tests/test_websockifyserver.py
+++ b/tests/test_websockifyserver.py
@@ -86,7 +86,7 @@ def test_normal_get_with_only_upgrade_returns_error(self, send_error):
             FakeSocket(b'GET /tmp.txt HTTP/1.1'), '127.0.0.1', server)
 
         handler.do_GET()
-        send_error.assert_called_with(405, ANY)
+        send_error.assert_called_with(405)
 
     @patch('websockify.websockifyserver.WebSockifyRequestHandler.send_error')
     def test_list_dir_with_file_only_returns_error(self, send_error):
@@ -96,7 +96,7 @@ def test_list_dir_with_file_only_returns_error(self, send_error):
 
         handler.path = '/'
         handler.do_GET()
-        send_error.assert_called_with(404, ANY)
+        send_error.assert_called_with(404)
 
 
 class WebSockifyServerTestCase(unittest.TestCase):
diff --git a/websockify/websocketproxy.py b/websockify/websocketproxy.py
index 8cfcd402..9b4595b4 100644
--- a/websockify/websocketproxy.py
+++ b/websockify/websocketproxy.py
@@ -327,8 +327,11 @@ def __init__(self, RequestHandlerClass=ProxyRequestHandler, *args, **kwargs):
             self.target_port = sock.getsockname()[1]
             sock.close()
 
+            # Insert rebinder at the head of the (possibly empty) LD_PRELOAD pathlist
+            ld_preloads = filter(None, [ self.rebinder, os.environ.get("LD_PRELOAD", None) ])
+
             os.environ.update({
-                "LD_PRELOAD": self.rebinder,
+                "LD_PRELOAD": os.pathsep.join(ld_preloads),
                 "REBIND_OLD_PORT": str(kwargs['listen_port']),
                 "REBIND_NEW_PORT": str(self.target_port)})
 
diff --git a/websockify/websockifyserver.py b/websockify/websockifyserver.py
index 8b33b3aa..74f9f536 100644
--- a/websockify/websockifyserver.py
+++ b/websockify/websockifyserver.py
@@ -250,13 +250,13 @@ def do_GET(self):
             self.auth_connection()
 
         if self.only_upgrade:
-            self.send_error(405, "Method Not Allowed")
+            self.send_error(405)
         else:
             super().do_GET()
 
     def list_directory(self, path):
         if self.file_only:
-            self.send_error(404, "No such file")
+            self.send_error(404)
         else:
             return super().list_directory(path)
 
@@ -277,7 +277,7 @@ def do_HEAD(self):
             self.auth_connection()
 
         if self.only_upgrade:
-            self.send_error(405, "Method Not Allowed")
+            self.send_error(405)
         else:
             super().do_HEAD()