MC7710 "forgetting" RAT

Martin Anderseck Martin.Anderseck at
Wed Feb 5 07:35:04 PST 2014

Bjørn Mork <bjorn at> wrote on 05.02.2014 15:37:21:
> It is probably worth noting that the AT!SELRAT command affects the same
> firmware settings as QMI, but does a combination of "technology" and
> "system-selection" preferences.
> So if MM touches any QMI setting, then this will be directly reflected
> in the AT command.  For example:
> bjorn at nemi:~$ qmicli -d /dev/cdc-wdm0 
> [/dev/cdc-wdm0] Successfully got system selection preference
>         Emergency mode: 'no'
>         Mode preference: 'lte'
>         Band preference: 'gsm-dcs-1800, gsm-900-extended, gsm-900-
> primary, gsm-pcs-1900, wcdma-2100, wcdma-900'
>         LTE band preference: '1, 3, 7, 8, 20'
>         Roaming preference: 'any'
>         Network selection preference: 'automatic'
>         Service domain preference: 'ps-only'
>         Service selection preference: 'automatic'
> at!selrat?
> !SELRAT: 06, LTE Only

Thank you also for this explanation. I've checked this while the RAT was 
valid and I got an output as yours. In the meantime I have also updated 
libqmi to 1.8.0 and ModemManager to 1.2.0. In this new setup I didn't see 
the wrong RAT yet but the first simple-connect attempt often ends in "QMI 
protocol error (79): 'PolicyMismatch'. I need to reset the modem but 
afterwards everything works without any problem. 

Unfortunately I cannot say that this problem is limited to my single 
MC7710. We use some of these modems in a project where partners make their 
first steps with them currently and I got that feedback twice already. But 
from all your statements it sounds like there's something strange going on 
in the modem and rather not in ModemManager. 

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