How to enable ADB interface for RM520N-GL

How to enable ADB interface for RM520N-GL
qadbkey is below.

[2024-06-11_11:14:53:571]+QADBKEY: 29442446



I tried but it showed error.
Please let me know why it didn’t work.


Please check the quotaion marks.

Someone provide this.

Unfortunately, I couldn’t connect any device, it disappeared Modem port(Quectel USB Modem) and COM & LPT(Quectel USB AT Port, USB DM Port, USB NMEA Port) after write adb key. Just show “Other devices” as below image.
Please check this issue.

But how you can send AT command?
You didn’t install any Quectel driver.

As I mentioned, it showed problem after write adb key thru AT command.
Do you have any idea which can recover.
Byoungchul Kim

Please check the USB VID and PID of the unknown USB device.

Or maybe you reinstall the USB driver.

As far as I guess, you have modify the USB VID and PID with the command AT+QCFG=“usbcfg”.

You’re right.
It seems that change VID/PID thru AT+QCFG=‘usbcfg’.
Can I recover original VID/PID?

Vendor ID : 0x0001 (Fry’s Electronics - OBSOLETE)
Product ID : 0x0001

As far as I know, you have two choice

  1. If the adb is working ,you can send AT command via /dev/smd7
  2. If you have a Linux PC, you can plug the RM520N-GL into the Linux PC.
    You can send AT command in the Linux PC.

adb doesn’t work still now.
Even if I have linux PC, it looks like that linux doesn’t recognize RM520N-GL.

If it is Linux, please check

lsusb -t

for example, if the VID and PID is 0x0001 and 0x0001,

modprobe option
echo 0001 0001 > /sys/bus/usb-serial/drivers/option1/new_id

Then you can see the ttyUSB.

Thnak to your support, I’ve seen ttyusb0, ttyusb1, ttyusb2, ttyusb3, ttyusb4. in /dev/ directory.
Will you please kindly explain how to send AT command on Linux.
I’m not familiar with linux.

If it is Ubuntu PC please try:

sudo systemctl stop ModemManager
sudo systemctl disable ModemManager

busybox microcom /dev/ttyUSB2 -s 115200

And then you can send AT in the mcirocom.

I got AT command line on Ubuntu.
Then should I input special AT command like AT+QCFG=“usbcfg” which recover original PID/VID?
Please let me know detailed AT command.


Even if I changed PID/VID, but windows PC didn’t recognize RM520N-GL.
Is there any further action to recover?


The PID is 0x0321 but not 0x0801.

Thank you for your kidly support.
Finally, I solve this issue using AT+QCFG=“usbcfg”,0x2C7C,0x0801,1,1,1,1,1,1,0.
And I saw adb working perfectly.

Sorry for my mistake.
Yes it should be