{ USB_DEVICE(0x2C7C, 0x6002) }, /* Quectel EC200N-CN */

2)add zero packet mechanism

kernel_dir/drivers/usb/serial/usb_wwan.c

if (dir == USB_DIR_OUT) {
struct usb_device_descriptor *desc = &serial->dev->descriptor;
if (desc->idVendor == cpu_to_le16(0x2C7C))
urb->transfer_flags |= URB_ZERO_PACKET;
}

3） use ecm or rndis

kernel_dir/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
if (serial->dev->descriptor.idVendor == cpu_to_le16(0x2C7C)) {
__u16 idProduct = le16_to_cpu(serial->dev->descriptor.idProduct);
//Quectel EC200S's interface 0 can be used as USB Network device (ecm, rndis)
if (serial->interface->cur_altsetting->desc.bInterfaceClass != 0xFF)
return -ENODEV;
}
#endif
/* Store device id so we can use it during attach. */
usb_set_serial_data(serial, (void *)id);
return 0;
}

4）make menuconfig

enable some modules

二、

uboot set bootcmd and bootargs

setenv bootcmd 'mmc dev 0; fatload mmc 0:1 80800000 zImage; fatload mmc 0:1 83000000 imx6ull-alientek-emmc.dtb; bootz 80800000 - 83000000;'
setenv bootargs 'console=ttymxc0,115200 root=/dev/mmcblk0p2 rootwait rw'

saveenv

三、

sd card make partitions and move zImage .dtb and rootfs to sd card

make partitions, init partitions, mount, cp：sd卡分区，fdisk 分区1 fat格式 分区2 ext4格式；mkfs.vfat mkfs.ext4格式化分区1、2；mount挂载分区1 分区2到虚拟机上，-t指明要挂载的文件系统类型，df -h查看挂载情况；cp复制内核镜像、设备树到分区1，复制根文件系统到分区2

四、

ecm 设置