Odd MM Bearer behavior

[Aleksander Morgado]

Hey,

> Current specs:
> mmcli 1.14.2
> qmicli 1.26.0

You should probably ping balena OS to upgrade those, at least to the
latest stable updates on those release branches.

> Quectel EG25G, firmware EG25GGBR07A08M2G. * Note, I also tested this with four other modems of varying models (i.e EC25A) with the same issue.
>
> root at 325da06:~# qmicli -d /dev/cdc-wdm0 -p --wds-get-profile-list=3gpp
> Profile list retrieved:
>         [1] 3gpp -
>                 APN: 'fast.t-mobile.com'
>                 PDP type: 'ipv4-or-ipv6'
>                 PDP context number: '1'
>                 Username: ''
>                 Password: ''
>                 Auth: 'none'
>                 No roaming: 'no'
>                 APN disabled: 'no'
>         [2] 3gpp -
>                 APN: 'ims'
>                 PDP type: 'ipv4-or-ipv6'
>                 PDP context number: '2'
>                 Username: ''
>                 Password: ''
>                 Auth: 'none'
>                 No roaming: 'no'
>                 APN disabled: 'no'
>         [3] 3gpp -
>                 APN: 'sos'
>                 PDP type: 'ipv4-or-ipv6'
>                 PDP context number: '3'
>                 Username: ''
>                 Password: ''
>                 Auth: 'none'
>                 No roaming: 'no'
>                 APN disabled: 'no'
>         [4] 3gpp -
>                 APN: 'tmus'
>                 PDP type: 'ipv4-or-ipv6'
>                 PDP context number: '4'
>                 Username: ''
>                 Password: ''
>                 Auth: 'none'
>                 No roaming: 'no'
>                 APN disabled: 'no'
>
> root at 325da06:~# qmicli -d /dev/cdc-wdm0 -p --wds-get-lte-attach-parameters
> error: Unknown option --wds-get-lte-attach-parameters
>
> root at 325da06:~# qmicli -d /dev/cdc-wdm0 -p --wds-get-lte-attach-pdn-list
> error: Unknown option --wds-get-lte-attach-pdn-list
>
> Above errors unfortunately are a bit out of my control, considering the ModemManager version is controlled by Balena's OS which means upgrading would presumably require a release on their side.
> I'm wondering if perhaps the IoTDataWorks default APN of `m2mglobal` should be changed to 'fast.t-mobile.com' to test?

The profile being used for initial attach is probably the #1 above.
How about you clear that one, so that no explicit APN is requested
during the attach operation? Try:
$ sudo qmicli -d /dev/cdc-wdm0 -p
--wds-modify-profile="3gpp,1,apn=,pdp-type=ipv4v6"

And then make sure it reregisters, e.g. by reseting the device:
$ sudo qmicli -d /dev/cdc-wdm0 -p --dms-set-operating-mode=offline
$ sudo qmicli -d /dev/cdc-wdm0 -p --dms-set-operating-mode=reset

-- 
Aleksander
https://aleksander.es