MC7710 "forgetting" RAT

Aleksander Morgado aleksander at
Mon Feb 3 10:29:20 PST 2014

Hey Martin,

> I'm using a Sierra Wireless MC7710 (firmware v3.05.24) in QMI mode with
> ModemManager 1.1. From time to time simple-connect fails and
> ModemManager's debug mode writes:
> ModemManager[2852]: <debug> [1391442490.063506]
> [mm-iface-modem-3gpp.c:285] run_registration_checks_ready(): Modem not yet
> registered in a 3GPP network... will recheck soon
> From what I found it seems to have to make with the radio access
> technology RAT which the module uses in that time:
> !SELRAT: Unknown RAT mode. Use AT!SELRAT to set band.
> 00000001
> 00000000
> Is this anything that is touched by ModemManager somehow? Or can I rather
> consider this as a firmware bug as it sometimes changes during a reboot of
> the computer it is built into? Before the reboot it is usually set to 0 or
> 7 but I don't even know how to set two rows into that field ;-)

ModemManager doesn't automatically set either bands or allowed modes
(e.g. 2G/3G/4G preference). Those changes are only done if the user
requests them (e.g. through --set-allowed-modes or --set-current-bands
in mmcli). When using mmcli to do those changes, and if the modem is
handled with QMI, ModemManager will use QMI itself to perform those
changes (e.g. no AT!SELRAT command).

If you can gather debug logs of ModemManager when the issue happens we
could try to know what could be really happening.


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