new file:   overlay/packages/apps/Settings/config.xml
<!-- Hardware Keys -->
    <bool name="config_has_hardware_buttons">true</bool>

modified:   overlay/frameworks/base/core/res/res/values/config.xml
<!-- Hardware "softkeys" present on the device, stored as a bit field.
         This integer should equal the sum of the corresponding value for each
         of the following keys present:
            1 - Home
            2 - Back
            4 - Menu
            8 - Assistant (search)
           16 - App switch
        For example, a device with Home, Back and Menu keys would set this
        config to 7. -->
    <integer name="config_deviceHardwareKeys">7</integer>
    <!-- Allow the menu hard key to be disabled in LockScreen on some devices -->
    <bool name="config_disableMenuKeyInLockScreen">true</bool>