Starting with IFD4XX/5XX SW release 10.2.4.1 there is an option to "Password Protect" the configuration of the IFD in maintenance mode by setting a PIN which will prevent changing the configuration pages with the exception of the WiFi page and Bluetooth page.
You can use the attached file to remove the pin. Once the pin has been removed, none is required though the page will always be there, you can simply pass it up and configure as you normally would.
If you inadvertently input anything here, the page will save it as a pin and you'll be back to square one.
To execute the file, simply load to FAT32 formatted USB and insert into powered OFF unit. Power IFD on> unit will wake up in MX mode > toggle to UPDATE tab> select file by placing green check mark using bottom right knob like button or touch screen> hit PROCEED. All should run with no errors.
If you wish to re-establish the PIN, please do so AFTER configuration changes have been completed and share this pin with the end user.