Issue with dual SIM and AUTO_SIM feature

Aleksander Morgado aleksander at
Wed Apr 14 07:33:46 UTC 2021

Hey Alexey

> This is a follow up on the recently discussed issue with EM7511 and the AUTO-SIM feature. When the carrier is set to AUTO_SIM, the modem will automatically set the appropriate profile, and reboot for this profile to take effect.
> A recent version of MM temporarily switches to every installed SIM during probing, in order to retrieve SIM information. The logic is summarized in the commit message
> Unfortunately, what we observe is these two features together seem to cause an infinite reboot loop after a SIM switch.

We've been discussing this issue in gitlab in the past months due to
different issues that have been found with this logic, and finally
decided that it was better to avoid the "hidden" SIM switching during
init. This is already merged in git master, and the commit lists a
collection of reasons why the change was done, I think it's properly

Note that we should not lose the ability to detect whether there are
SIM cards on other slots, and we should also be able to report ICCID
for each of the non-active SIM cards. What we lose is MCCMNC, operator
name, and other secondary things like list of emergency numbers and so
on on the non-active ones.

My only concern right now is whether this change should go into MM 1.16 or not.


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