The easiest way is one line in the terminal, then reboot. Here is the line to copy paste:
echo 'ACTION=="add", SUBSYSTEM=="usb", ATTR{idVendor}=="2020", ATTR{idProduct}=="2060", TEST=="power/control", ATTR{power/control}="on"' | sudo tee /etc/udev/rules.d/99-usb-modem-always-on.rules
(the terminal will ask for your password, that’s normal. The password is your PIN code, not the disk encryption password). After the reboot, you can check that the usb is forced to “on” with this command:
cat /sys/bus/usb/devices/1-1.2/power/control
If this does not solve any problem for you after a few days of test, you can rollback with this command:
sudo rm /etc/udev/rules.d/99-usb-modem-always-on.rules