I see these warnings in the journalctl after every boot, on Ubuntu 15.10:
```
Dec 11 09:18:08 M2 ModemManager[816]: <warn> Could not grab port (tty/ttyS4): 'Cannot add port 'tty/ttyS4', unhandled serial type'
Dec 11 09:18:08 M2 ModemManager[816]: <warn> Couldn't create modem for device at '/sys/devices/pci0000:00/0000:00:16.3': Failed to find primary AT port
Dec 11 09:18:08 M2 ModemManager[816]: <warn> Modem couldn't be initialized: Couldn't check unlock status: SIM not inserted
```
Any clues what this could be and why modem can't be initialized?
I see these warnings in the journalctl after every boot, on Ubuntu 15.10:
``` pci0000: 00/0000: 00:16.3' : Failed to find primary AT port
Dec 11 09:18:08 M2 ModemManager[816]: <warn> Could not grab port (tty/ttyS4): 'Cannot add port 'tty/ttyS4', unhandled serial type'
Dec 11 09:18:08 M2 ModemManager[816]: <warn> Couldn't create modem for device at '/sys/devices/
Dec 11 09:18:08 M2 ModemManager[816]: <warn> Modem couldn't be initialized: Couldn't check unlock status: SIM not inserted
```
Any clues what this could be and why modem can't be initialized?