diff --git a/loraserv.py b/loraserv.py
index 38c3747..e60b3b0 100644
--- a/loraserv.py
+++ b/loraserv.py
@@ -78,7 +78,7 @@ async def main():
 	args = parser.parse_args()
 
 	# open up the gateway device
-	reader, writer = await open_dev(args.serdev, 'w+b')
+	reader, writer = await open_dev(args.serdev, 'w+b', buffering=0)
 
 	# open up the listener
 	mr = await multicast.create_multicast_receiver(DEFAULT_MADDR)
@@ -197,7 +197,7 @@ class TestLoraServ(unittest.IsolatedAsyncioTestCase):
 			await main()
 
 		# that open_dev is called with it
-		od.assert_called_with(serdev, 'w+b')
+		od.assert_called_with(serdev, 'w+b', buffering=0)
 
 		# and that the multicast functions were called
 		cmt.assert_called_with(DEFAULT_MADDR)