diff --git a/pyocd/utility/rtt_server.py b/pyocd/utility/rtt_server.py
index 8b752b11b..def7d083b 100644
--- a/pyocd/utility/rtt_server.py
+++ b/pyocd/utility/rtt_server.py
@@ -300,7 +300,7 @@ def get_down_data(self):
                 LOG.debug("Received non-hello message from SystemView client before hello message; ignoring")
             return b''
 
-        return data
+        return data[1:data[0] + 1]
 
 class RTTChanStdioWorker(RTTChanWorker):
     """@brief Implementation of channel worker that forwards RTT data via a STDIO"""