we at Witzenmann develop an IoT device with the GM02S modem. With the modem firmware version LR8.2.1.0-61488 I did not have any critical our periodic errors.
However after updating two of our test devices to modem firmware version LR8.2.2.1-63493 I get a periodic behaviour:
The modem connects successfully to an operator, and establishes an MQTT connection using TLS
After approx 6 hours while trying to publish a new MQTT message, it fails
Suddenly neither operator, nor PDP context nor a signal quality ist there
Detailed print of the AT commands:
Check registration status with CEREG command
CEREG resbuf: 3,5,“B87F”,“01176303”,7
CEREG res: 5
CEREG stat: 5
Connected to network
MQTT connected
Sending new telemetry message:
[INFO] Publishing message..
[WARN] Timed out waiting for publish confirmation. Consider increasing timeout for publishing
[ERROR] Failed to publish
-—Start loop----
Current Device: 1
manhole state as Random number: 1
Check registration status with CEREG command
CEREG response: 3,0
CEREG stat: 0
[ERROR] Failed to retrieve the operator name.
currentOper: NOT_AVAILABLE
[ERROR]: No operator available!
CSQ res: 99
+CGATT:
After resetting the device and so deatach and reatach the modem to the network it connects immidiatly. I had already contact with our operator, who have made an investigation and did not found any disturbance or error on their side.
Do you have any information of this kind of issue?
n = 3 — this is the mode parameter, meaning unsolicited result codes are enabled with network registration and location information (+CEREG: <stat>[,<tac>,<ci>,<AcT>]), not an error code itself.
stat = 0 — this is the actual registration status.
stat = 0 means:Not registered — the mobile terminal (MT) is not currently searching for an operator to register with.
Then It look like the LTE network connection and it might need to get SQN DM(Debug & monitor tool) log for further analysis. Then may I know if you have already install SQN DM tool on your host PC for this kind of trouble shooting?
thank you for your quick reply! I have not used the SQN DM Tool yet, but I can download it. Do you have any requierment or software how/what I should use for the tool? Or are you just interested in special AT command replies? Thank you for your help!
1\ Please download SQN DM light tool from SharePoint
2\ Install DM light tool on your host PC and connect to GM02S
3\ Start DM light tool and take the attached DM log mask “[GM02S]LTE_network_connection.dmrec” to collect DM log.
The DM log mask file can be replaced while you press “start record” → “change configuration” then select the specific DM log mask file.
thank you for your quick response and guide!
For clarification, should run on my test device my test program during the logging with the DM Tool? I ask because I can connect with the device only if I use an UART Bridge on the test device, wich gives direct Serial access to the modem. Othevise the DM tool can not connect via UART.
Best Regards
Yes, it would be better if you could run your application while collecting the logs. I believe this will help reproduce the issue and capture more relevant information.
The GM02S has three UART interfaces. Therefore, it should be possible to connect both the GM02S and the DM Light Tool through one UART, while allowing your application to communicate with the GM02S through a separate UART. Alternatively, does your board provide only a single UART connection to the GM02S?
thank you very much for your reply. This is a good suggestion. For the test device I am using the AVR-IoT-Cellular board (AVR-IoT Cellular Mini | Microchip Technology). I could solder on the board at the UART1 and/or UART2 vias holes a connector and connect it to an UART to USB bridge. (See picture)
I hope in this way I can run my test firmware, while reading the UART interface of the GM02S directly. I will send you then the log file as soon as possible, or ask any further questions if necessary.
Not sure which MQTT version you are testing with, there is MQTT disconnect issue in LR8.2.2.1-63493. I suggest you can try the latest LR8.2.3.1-65130 release which include fix of MQTT connect issue and also add MQTT v5 support.
thank you for your suggestion. Unfortunately I do not have access to the LR8.2.3.1-65130. The latest version in the Sequans cloud I have access is the one with the issue. However with the previous version LR8.2.1.0-61488 I did not experienced this issue. So we use for the customer products this one until then.
I have completed the analysis of the log “015770000621384_2026-09-17-10h24m44_part19.evt”.
Based on the log analysis, the LTE modem remains attached to the LTE network. As shown in the partial log in below, the modem continues to receive paging messages, which indicates that it remains connected to the network. Therefore, the log does not show any LTE network connectivity issue as described in the initial problem statement.
If you are still observing the MQTT session issue during testing, it would be worthwhile to upgrade the software to LR8.2.3.1-65130 first, as recommended by Eros.
Note:LR8.2.3.1-65130 is already available on the SQN SharePoint site.
thank you for your time and help. I see the software is in the sharepoint site and not in the Sequans Clouad platform. I have found the firmware version LR8.2.3.1-65130 and I will test with this version.
