Enable Huawei K4203 Cellular Internet dongle on Linux

12d1:1f1c

TargetVendor=0x12d1
TargetProduct=0x1f1c
MessageContent="55534243123456780000000000000011062000000101000100000000000000"

40-usb_modeswitch.rules

ATTRS{idVendor}=="12d1", ATTRS{idProduct}=="1f1c", RUN+="usb_modeswitch '%b/%k'"

install.sh

#!/bin/bash

#Install udev rule
cp ./12d1\:1f1c /etc/usb_modeswitch.d/

#Install usb modeswitch rule
cp ./40-usb_modeswitch.rules /etc/udev/rules.d/

On Raspbian Stretch usb_modeswitch seems not to be able to identify the device correctly using this method. Specifying the options directly to the command works, as follows:

ATTRS{idVendor}=="12d1", ATTRS{idProduct}=="1f1c", RUN+="/usr/sbin/usb_modeswitch -v 12d1 -p 1f1c -M 55534243123456780000000000000011062000000101000100000000000000"

Just to add I have the same issue, running it as @webworxshop recommends works. This goes into the 40-usb_modeswitch.rules file for anyone interested.