Firmware update problem on RM520N-GL

Technical Subjects Upgrade/Debug
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1

Hello all,

I have a Quectel RM520N-GL 5G modem that I’m using to tinker with mobile networks.
It had a very old firmware version (RM520NGLAAR01A02M4G from ATI command), and although it was working fine with 5GNR TDD bands, it was not connecting to FDD bands, so I wanted to update the firmware to see if it would improve.

I used QFlash V6.9 in Windows 11 to update to a few newer versions that I found online ( RM520NGLAAR01A06M4G, RM520NGLAAR01A07M4G, RM520NGLAAR01A08M4G), but now the modem is not connecting to the cellular network.
I cannot set a PDP context (AT+CGACT=1,1 always gives me a CME ERROR 100 response), and I cannot even set the modem to full functionality (AT+CFUN=1 returns CME ERROR 0, AT+CFUN=0 returns CME ERROR 4, and AT+CFUN? command returns CFUN: 7). Is there anything I can do? Can I go back to the previous firmware version and have it working again?

Thank you, best regards.

2

Hi,@miguelvf
What other operations did you perform? CFUN=7，It’s possible that the file system is corrupted.
It is better to contact with manufacture to solve it.
Or your device have USB port and backup some file to confirm.

3

I just tried doing the firmware update. It seems like you said that the file system has gone corrupt. I have the modem on a normal USB daughter board, but I didn’t do any backup. I’ll see if maybe trying to flash other firmware version might help.