With the aforementioned udev rules file, the situation got much better. However, it is not perfect. In some occasions (about 20~30% of resumes), the modem is still unusable, and when this happens, only a reboot can help to get it usable again.
With the aforementioned udev rules file, the situation got much better. However, it is not perfect. In some occasions (about 20~30% of resumes), the modem is still unusable, and when this happens, only a reboot can help to get it usable again.