lsusb does see the device. Sierra EM7455
Tried to add a new mobile broadband connection.
Under all connections "mobile broadband not enabled" grayed out
Any help would be appreciated
I managed to get the Sierra EM7455 working on my Thinkpad X1 4th gen. I did try a few things before it worked, so hopefully the below description is complete.
I upgraded the modemmanager package to the one from Ubuntu 16.10 by downloading the
.deb package and then installing it using the
dpkg -i command. Apparently the Sierra EM7455 expects some “FCC auth” command at startup which is implemented in modemmanager 1.6.0
The modemmanager package has some dependencies but I just downloaded and installed these as well:
libmbim-glib4_1.14.0-1_amd64.deb libmbim-proxy_1.14.0-1_amd64.deb libmm-glib0_1.6.0-1_amd64.deb libqmi-glib5_1.6.0-1_amd64.deb modemmanager_1.6.0-1_amd64.deb
I also upgraded to the 4.7.2 kernel. I am unsure if this is actually necessary or if the current default kernel for 16.04 has been patched.
It took me the better part of two evenings to make it work, so hopefully this can help you as well.
After doing what @zanna describes, you still need to do the following for network manager to get an IP address.
sudo rfkill unblock wwan
sudo mbim-network /dev/cdc-wdm1 start
sudo mbim-network /dev/cdc-wdm1 stop
note your modem might be /dev/cdc-wdm0 or some other integer