Comment 31 for bug 875441

This is not something we can use as a workaround, since you'd be losing USB2 which has a purpose (otherwise it wouldn't be provided).

This needs a fix in the modemmanager whitelist udev rules, or in the kernel driver in use.

These are the revelant udev lines from modemmanager's /lib/udev/rules.d/77-mm-zte-port-types.rules:

ATTRS{idProduct}=="0033", ENV{.MM_USBIFNUM}=="04", ENV{ID_MM_ZTE_PORT_TYPE_MODEM}="1"
ATTRS{idProduct}=="0033", ENV{.MM_USBIFNUM}=="01", ENV{ID_MM_ZTE_PORT_TYPE_AUX}="1"

Could you please run 'sudo lsusb -d 12d1:0033' with the device plugged in, so we can see if there's something going wrong with how the ports are detected?

I suspect what is likely required here is either that these values are plain wrong, or as a more likely scenario your device uses a different firmware version than what was tested and lists its ports in a different order.