GM02S modem always returns ERROR after any AT command

LTE-M / NB-IoT (Monarch)
1

Hi,

probably due to flash corruption on 8.2.0.2 fw, I am not able to send any AT command. The modem always answer “ERROR” after each command (and no +SYSSTART at startup is sent from the modem). Is there any mean to fix that or I have to replace the device ?

Thanks !

2

Hi Pascal,

Usually, there is always a way to recover the modem. Since it is 8.2.0.2 fw, I assume that you are using a GM02S module. The modem seems to be in RECOVERY boot mode and is waiting for FW upgrade. Do you remember the last actions that were done with the modem before this situation ? Was software upgrade through UART interrupted ? If yes, you can usually re-run the sfu upgrade command, and it will work.

Try this procedure to upgrade to the latest FW:

  1. Download GM02RBAQ-DM_LR8.2.2.1-63493.dup.tgz for GM02S from https://cloud.sequans.com/f/4822510 and extract the .dup file from the archive

  2. Install SFU on Windows PC from https://cloud.sequans.com/f/413573

  3. Open a command prompt to the folder where you saved the .dup file

  4. Run this command:

    “c:\Program Files (x86)\Sequans Communications\SFU\sfu.exe” upgrade -t 115200,921600 -b 921600 --no-signature-verification COMXX GM02RBAQ-DM_LR8.2.2.1-63493.dup

    Where COMXX is the COM port that replies ERROR in your initial comment.

If it does not work to recover the board, please send me the SFU log.

Also, if you have access to GM02S UART2 @ 115200 bps, no flow control, then, connect a terminal to this port and get the log when you power up the modem and run the sfu upgrade command, copy paste the sfu and uart2 logs here. It must give us a clue on the state of the modem.

Best regards,

Benoit.

3

Thank you Benoit, it works !

I had to make the procedure twice.

You can close the ticket.

Thanks, Pascal