modemmanager breaks Pantech UML295W Ubuntu 14.04

[Zero]

Computer is a Asus 1215n. This verizon wireless air card worked great on Xubuntu 12.04, 12.10, 13.04 and 13.10. Broken when I upgraded to 14.04.

I have posted a great deal of additional system diagnostic info in this thread
http://ubuntuforums.org/showthread.php?t=2239564

The only BandAid that has worked so far is to regress modemmanager from 1.0.0-2ubuntu1 to 0.5.2.0-0ubuntu2.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: modemmanager 1.0.0-2ubuntu1
ProcVersionSignature: Ubuntu 3.13.0-39.66-generic 3.13.11.8
Uname: Linux 3.13.0-39-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.5
Architecture: amd64
Date: Sat Nov 8 12:17:48 2014
EcryptfsInUse: Yes
ExecutablePath: /usr/sbin/ModemManager
InstallationDate: Installed on 2014-01-22 (290 days ago)
InstallationMedia: Xubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016)
ProcEnviron:
 PATH=(custom, no user)
 TERM=linux
SourcePackage: modemmanager
UpgradeStatus: Upgraded to trusty on 2014-07-09 (121 days ago)

[Zero (zerofossilfuel)]

Upgraded tonight to Xubuntu 14.10 Utopic Unicorn. modemmanager 1.2.0-1 still exhibits exactly the same problem. I am again regressing and pinning modemmanager to 0.5.2.0-0ubuntu2. Very disappointing.

[Mathieu Trudel-Lapierre (cyphermox)]

Please attach /var/log/syslog to this bug report after reproducing the issue; this will make it possible to see exactly what is happening when the device is detected by ModemManager and NetworkManager.

Thanks!

[Zero (zerofossilfuel)]

As stated above in my initial bug report, I have posted a great deal of additional system diagnostic info in this thread
http://ubuntuforums.org/showthread.php?t=2239564

Syslog is the 1st post. Attached here per your request.

[Sabree Blackmon (delete-pyou)]

I've run into this exact same issue with modemmanager 1.0.0-2ubuntu1 running Linux Mint 17.1. Downgraded to 0.5.2.0-0ubuntu2, and the modem works as specified and is stable.

[Sabree Blackmon (delete-pyou)]

I've run into this exact same issue with modemmanager 1.0.0-2ubuntu1 running Linux Mint 17.1. Downgraded to 0.5.2.0-0ubuntu2, and the modem works as specified and is stable.

[Marius B. Kotsbak (mariusko)]

I have backported modemmanager packages available for Ubuntu 14.04 available here if anyone want to test: https://launchpad.net/~mariusko/+archive/ubuntu/network-manager-backports?field.series_filter=trusty

[Nick (nbrachet)]

@mariusko no change with your backported modemmanager packages.

[james wilson (honkyusa3)]

upgraded from 12.04 LTS to 14.04 LTS and experienced the same exact issue with my Verizon Pantech 4G USB stick. as suggested, I downgraded modemmanager and everything appears to be stable.

[Launchpad Janitor (janitor)]

[Expired for modemmanager (Ubuntu) because there has been no activity for 60 days.]

[Zero (zerofossilfuel)]

Finally upgraded from 14.04 to 14.10 (mm v1.2), then 15.04 (mm v1.4). Tested my Pantech device with each version. Even with Vivid, I still have to regress my modem manager to version 0.5.2.0-0 in order for my Pantech UML295W to work.

This appears to be a permanent regression with no urgency assigned to ever repairing it. Very disappointing.