diff --git a/RFXtrx/lowlevel.py b/RFXtrx/lowlevel.py
index 7c1a681..04afe7e 100644
--- a/RFXtrx/lowlevel.py
+++ b/RFXtrx/lowlevel.py
@@ -703,7 +703,7 @@ def _set_strings(self):
             if self.cmd2 in self.COMMANDS:
                 self.cmnd_string = self.COMMANDS[self.cmd2]
             else:
-                self.cmnd_string = self._UNKNOWN_CMND.format(self.cmd2)
+                self.cmnd_string = self._UNKNOWN_CMND.format(self.cmd)
 
 
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