RM520N AT Command Not Responding and Device Manager Reloading Issue

IoT Modules 5G Module
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1

Dear Quectel Support Team,

I am using a Quectel RM520N-GL module on a GL-M2 5G development board.

After upgrading the firmware, I encountered the following problems:

  • The AT port exists, but AT commands do not respond.
  • Device Manager keeps refreshing/reloading continuously.
  • Sometimes the device connection becomes unstable.
  • I tried using PuTTY, TeraTerm, QPST, and QFIL, but the issue remains.

Current firmware version:
RM520NGLAAR03A04M4G_01.202.01.202

Current status in Device Manager:

  • Quectel USB AT Port (COM12)
  • Quectel USB DM Port (COM17)

The module is not in 9008 mode and can boot normally, but AT commands cannot be used.

I have already tried reinstalling drivers, reflashing firmware, and resetting the device, but without success.

Could you please help me with one of the following:

  1. Provide a debug/development firmware or full recovery firmware for RM520N, or
  2. Provide instructions to restore normal AT command function and USB configuration.

If needed, I can provide the module serial number, logs, and screenshots.

Thank you very much for your support.

2

Dear @Phuc_Tr_ng
Please share a picture of your RM520N, I need check the information in shield cover.

3

Thank you for your reply.

Please find the attached picture of my RM520N-GL module with the shield cover information.

Details from the shield:

  • Model: RM520N-GL

  • Variant: RM520NGLAA-M20-SGASA

  • SN: MPY25G41N001223

  • IMEI: 868371055337907

This module shows the same issue on different boards and PCs:

  • AT command not responding

  • Device Manager reloading continuously

  • AT and DM ports exist, but AT cannot be used

Please let me know if you need any additional information or logs.

Thank you very much for your support.

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4

Hello @silvia

Just a gentle follow-up regarding my RM520N-GL module issue.

I have attached the shield cover picture and provided the module details in my previous reply.
Could you please check when you have a moment?

Thank you very much for your support.

5

Dear @Phuc_Tr_ng
Device Manager reloading continuously seems the module was rebooting.

I have sent the firmware to you, you can try to upgrade.

6

Dear @silvia
I’ve already tried the firmware you sent, but the issue hasn’t improved. Could you please assist me via TeamViewer?

7

Dear @Phuc_Tr_ng
Do you install corresponding driver with USBNET?

8

@silvia, I also found same issue from yesterday, even I have done same procedure before as well, and it works.

Could you also guide me on W_DISALEB2 Pin functionality Status !?
As it Hardware Design guide, it’s mentioned that it is under development (W_DISABLE #*), so can we assume that by default GNSS functionality is running, and not required to give pull up from source and attach pin to GPIO in host.

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9

Dear @avi951
You can use AT command to enable or disable GNSS.
GNSS function is disabled by default.

10

Yes, I have already installed the corresponding USBNET driver