MC7750 missing SIM until ModemManager restart

[Dan Williams]

On Thu, 2018-10-11 at 00:37 +0200, Aleksander Morgado wrote:
> On Thu, Oct 11, 2018 at 12:32 AM Bowden, Brendan <bbowden at presidio.co
> m> wrote:
> > 
> > > 
> > >    Out of curiosity, have you tried different SIM cards?
> > >    Also, is the firmware you're using the latest one available
> > > for the MC7750?
> > > 
> > 
> > Multiple SIM cards on multiple machines are acting the same way. We
> > were originally running FW 3.5.10.6; behavior didn't change going
> > to the last available FW 3.5.10.13.
> > 
> 
> Ok, then the optional recheck loop, as we do for MBIM modems, could
> help here.
> Tracking it here:
> https://gitlab.freedesktop.org/mobile-broadband/ModemManager/issues/8
> 9

I don't recall ever seeing this issue with my MC7750, but it's been at
least a year or so since I tried it.  My VZW SIMs were all from the
2010 - 2012 timeframe though, perhaps newer SIMs are different and have
some effect here.  We've had that kind of problem before, where newer
SIMs interact badly with older firmware (Icera devices and ISIS-enabled 
SIMs).

Dan