AW: Assistance Needed with SIM Card Issue Causing QMI Operation Failures

Ralf Glaser glaser at
Mon Feb 5 12:20:30 UTC 2024


i'm seeing similar (not necessarily related) problems with an EC21 when using Telefonica SIM cards (other cards work fine, these work sporadically). It seems as if those cards have a longer startup time. With the following patch the cards work most of the time (ModemManager 1.18.6):
 src/mm-iface-modem.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/mm-iface-modem.c b/src/mm-iface-modem.c
index 8bf0893c01a2..be05bf4a7a8b 100644
--- a/src/mm-iface-modem.c
+++ b/src/mm-iface-modem.c
@@ -420,7 +420,7 @@ mm_iface_modem_abort_invocation_if_state_not_reached (MMIfaceModem          *sel
  * are modems on which the SIM takes more than 15s to be ready, luckily,
  * they happen to be QMI modems where the SIM's iccid in load_sim_slots
  * lets us know that there is a sim */

 /* Time between retries */

I have no idea why this patch is working since the EC21 is a QMI modem which, according to the comment,  should not be affected by this...

If someone with a deeper understanding of ModemManagers internals would like to look into this i would be happy to offer my support.

Best regards,

Von: ModemManager-devel <modemmanager-devel-bounces at> im Auftrag von Daniel Edwards <daniel.edwards at>
Gesendet: Donnerstag, 1. Februar 2024 17:48
An: modemmanager-devel at <modemmanager-devel at>
Betreff: Assistance Needed with SIM Card Issue Causing QMI Operation Failures


I'm reaching out to seek guidance regarding an issue I've been experiencing with ModemManager, specifically related to certain SIM cards causing QMI operation failures, which ultimately leads to the modem being marked as invalid.

To give you a brief overview, the modem still responds to AT commands and shows that it's connected and registered to the correct home network, but the modem will not show in mmcli -L, and the device will stay unconnected. With other SIMs it will work fine.

The modem is a SIM7600G.

Here is a log with --debug enabled

Sometimes the problematic SIM will work and connect the device to the internet, but I have not found a way to reliably recreate this scenario.


Daniel Edwards
Q Yachts Oy

Technical Engineer

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