EG25 can't read SIM

Technical Subjects Software General Function
1

I’ve got a Quectel EG25-G that suddenly cannot read the SIM. The modem is installed in a PCengines APU2d, and I’m running an OpenEmbedded Linux build based on Yocto. It worked for me several months ago, and a Sierra Wireless modem inserted in the same card slot is able to read the modem.

These lines from the ModemManager log seem most relevant:

Aug 30 20:26:42 url-000db95362a6 ModemManager[552]: [modem0] couldn’t query SIM slots: QMI protocol error (94): ‘NotSupported’
Aug 30 20:26:42 url-000db95362a6 ModemManager[552]: [modem0] state changed (unknown → locked)
Aug 30 20:26:42 url-000db95362a6 ModemManager[552]: [modem0] modem couldn’t be initialized: Couldn’t check unlock status: QMI operation failed: Illegal SIM/USIM application state
Aug 30 20:26:42 url-000db95362a6 ModemManager[552]: [modem0] state changed (locked → failed)
Aug 30 20:26:42 url-000db95362a6 ModemManager[552]: [modem0] couldn’t open ports during Modem SIM hot swap enabling: Couldn’t get primary port
Aug 30 20:26:42 url-000db95362a6 ModemManager[552]: [modem0] SIM is missing and SIM hot swap is configured, but ports are not opened.

Package revisions are:
ModemManager 1.18.4
libmbim 1.26.2
libqmi 1.30.2

Can anyone suggest where I should start in diagnosing this?

2

We have been seeing the exact same error.
done 100+ installs using the same ModemManager version, all at once sims seem to bee failing.

other debug information:
on first boot: sim seems to be found and working
it’s only after reboot that the error occurs in our case.

did you manage to fix the issue?

3

I’ve had no luck yet.

4

we installed another modem and the issue was resolved.
We assume therefore that the modem is malfunctioning.
How the modem broke in the first place - we don’t know.
if possible, that seems my best advice: try another modem

5

Yuck. I was afraid of that. How have you been turning off the modem? Do you issue a shutdown command to the modem, or do you kill power to the entire system? I’ve been working on a project in which the system is expected to be an unattended box, just like a router or switch, where battery backup isn’t available, so yanking power is considered normal operation. Perhaps the Quectel isn’t up to dealing with that.

6

indeed, we didn’t shut down the modem, we shut down the whole device.
And the issue hasn’t been reproduced since the modem has been replaced.
One option we considered for modem malfunctioning: that static somehow killed or damaged the modem during installation. But I suppose that is no option for your setup.

7

Static seems pretty unlikely in my situation. The modem was installed for several months before this happened, and the relative humidity in my office has been around 60% all summer.