diff --git a/cw/waverunner.py b/cw/waverunner.py
index 950a227b7..ab99b8fe0 100755
--- a/cw/waverunner.py
+++ b/cw/waverunner.py
@@ -115,7 +115,7 @@ def _get_and_print_cmd_error(self):
                      "EOI detected during definite length data block transfer.",
                      "Extra bytes detected during definite length data block transfer"]
         return_code = int((re.findall(r'\d+', self._ask("CMR?")))[0])
-        if return_code > 11:
+        if return_code > 13 or return_code in [8, 9]:
             return_msg = f"{return_code} Unkown error code"
         else:
             return_msg = f"{return_code} {error_msg[return_code]}"