Comment 83 for bug 408555

Also by default after plugging in and waiting ~80 seconds (time needed for the dongle to be recognized by system), "Enable Mobile Broadband" is unchecked in Network Manager, although broadband connections are available and it is possible to connect to them by clicking.
If I manually click the "Enable broadband connection" before connecting to a network, then connection is lost shortly to the modem and Network Manager no longer recognizes it, until reboot.
If the checkbox is left "as it is" and I simply connect to the desired network, then it is possible to unplug the dongle and then it will be recognized properly, when connected (takes ~80 seconds to start as well). Hope this info is of any use in tracking and fixing this bug.