HP lt4120 failing to make single-stack connections on LTE using MM

[Tore Anderson]

* Tore Anderson

> * Aleksander Morgado
>>>
>>>>     $ sudo mmcli -m 0 --reset
>>>
>>> Thanks - I had overlooked that one, but it doesn't quite work:
>>>
>>> error: couldn't reset the modem: 'GDBus.Error:org.freedesktop.ModemManager1.Error.Core.Unsupported: Cannot reset the modem: operation not supported'
>>
>> Oh wow, which MM are you using? This has been implemented for QMI
>> modems since a very long time ago.
> 
> Whatever's in Fedora - v1.6.12. Guess I should upgrade. :-)
I tried upgrading now (rebuilt the F29 SRPM):

$ rpm -qa ModemManager libmbim libqmi
ModemManager-1.8.0-4.fc28.x86_64
libqmi-1.20.0-2.fc28.x86_64
libmbim-1.16.0-2.fc28.x86_64

But still:

$ mmcli -m 0 --reset
error: couldn't reset the modem: 'GDBus.Error:org.freedesktop.ModemManager1.Error.Core.Unsupported: Cannot reset the modem: operation not supported'

$ mmcli -m 0 --factory-reset=000000
error: couldn't reset the modem to factory state: 'GDBus.Error:org.freedesktop.ModemManager1.Error.Core.Unsupported: Cannot reset the modem to factory defaults: operation not supported'

For what it's worth, these two commands result in no log output from MM
whatsoever, even with debug level logging active.

v1.8.0 ought to be on the right side of «a very long time ago», right?
There's no reason why this shouldn't work?

Tore