EC25-EU enters crash loop after CS Fallback

IoT Modules LTE Standard Module
1

Hi,

I’m using EC25-EU on differents countries, and some of them are entering some sort of crashloop / reset loop as soon as I tried a voice call (CS Fallback), or when I switch back to 2G/3G manually using AT+QCFG command.

The only way to go out of this crash/reset loop is to use a script to send AT command during the few ms the device is up, and force it to 4G only using AT+QCFG=“nwscanmode”,3

Is there any AT command and/or tools to debug this and see what happened ? I tried the same FW on another country / MNO, and it works fine …

Host OS : Raspberry Pi 4B+ with 4G LTE Hat.
Current FW (just upgraded) : EC25EUGAR06A11M4G_01.200.01.200

Thanks for your help,
BR,
Mathieu F.

2

Hi @Mathieu
Can you try the method I sent you in the chat box?

3

Hi @lyman-Q

Just tried these AT commands, and it didn’t fix the issue … Modem is still entering the crash “loop” after trying a voice call (CS Fallback)

BR,
Mathieu

4

Same with “EC25EUXGAR08A17M1G_A0.200.A0.200” lastest

5

FYI, I’ve set these AT commands to try to retrieve a coredump, and it looks like the device is not ‘crashing’ but just resetting … It didn’t enter in dump mode to download a coredump …
I’ve check power with AT+CBC and it appears the power is 3.8V so it’s seems OK as well

AT+QCFG="modemrstlevel",0
OK

AT+QCFG="aprstlevel",0
OK

AT+CBC
+CBC: 0,65,3825
OK