Has anyone successfully connected a verizon 290 USB modem to the Arduino Yun? I get as far as getting it to instAll itself as ttyACM0 and can run a ppd script without error, but the syslog shows that the connection always fails.
There was an issue with ttyACM0 stability that should be fixed in the latest yun image. Please, upgrade your yun and retry. Instructions at http://forum.arduino.cc/index.php?topic=235360.0