def get_current_phy_conf(update, device_id):
    """
    Lookup current configuration for a network device.

    This includes information such as the Wi-Fi channel.

    Returns a dictionary, which may be empty if no configuration was found.
    """
    hostConfig = update.cache_get('hostConfig')
    for dev in hostConfig.get('wifi', []):
        if dev.get('id', None) == device_id:
            return dev
    return {}
