Upon installing the firmware, at first boot, the software asks what flavor of QMX it's running on. You probably answered "20-10m" by mistake.
Make a long press on the left small button, the menu appears. Turn the right encoder to access "System config" then short press the left small button again, you should see "20-10m" selected. Short press the left small button, then turn the right encoder to select "80-20m". Short press the left small button to accept the change, then short press the right small button two times to exit the menu. Power cycle the QMX and you should be ok.
Alternatively, you can do a full factory reset (access the menu as shown above and scroll to "Factory reset") and select "80-20m" after the automatic reboot.
Regards,
YO3GFH
op. Adrian