4. Use GobiNet or QMI WWAN
File: [KERNEL]/drivers/usb/serial/option.c
static int option_probe(struct usb_serial *serial, const struct usb_device_id *id) {
struct usb_wwan_intf_private *data;
……
#if 1 //Added by Quectel
//Quectel UC20's interface 4 can be used as USB Network device
if (serial->dev->descriptor.idVendor == cpu_to_le16(0x05C6) &&
serial->dev->descriptor.idProduct == cpu_to_le16(0x9003)
&& serial->interface->cur_altsetting->desc.bInterfaceNumber >= 4)
return -ENODEV;
//Quectel EC20's interface 4 can be used as USB Network device
if (serial->dev->descriptor.idVendor == cpu_to_le16(0x05C6) &&
serial->dev->descriptor.idProduct == cpu_to_le16(0x9215)
&& serial->interface->cur_altsetting->desc.bInterfaceNumber >= 4)
return -ENODEV;
//Quectel EC21&EC25&EC20 R2.0's interface 4 can be used as USB Network device
if (serial->dev->descriptor.idVendor == cpu_to_le16(0x2C7C)
&& serial->interface->cur_altsetting->desc.bInterfaceNumber >= 4)
return -ENODEV;
#endif
/* Store device id so we can use it during attach. */
usb_set_serial_data(serial, (void *)id);
return 0;
}