EC20 partially bricked


I were testing the USB-Audio functionality, but something went wrong with AT+QCFG=“usbcfg”… command.
Now all ttyUSB devices disappeared, only /dev/cdc-wdm remains.

I tried factory reset via qmi-tool:
sudo qmicli -d /dev/cdc-wdm0 --dms-restore-factory-defaults=000000

but with no result.

Thanks for support

Dear Abietre,
Thanks for your inquiry in Quectel forum.
About your issue, it is better to share more information with us. What is wrong with the command “AT+QCFG=“usbcfg”” ? What have you done, could you describe your test steps, then we can help to confirm where is the problem.Thanks!

The command was issued by a script.
I fear AT+QCFG=“usbcfg”,0,0,0,0, so i think it disabled the serial interfaces.
After rebooting the device with AT+CFUN=1,1, the serial interfaces /dev/ttyUSB* disappeared.
The device is still reachable via the wdm interface.
I need a way to re-enable the serial interfaces for AT commands.

The platform is Ubuntu 20.04 on an x86-64 machine.


Dear Abietre,
Please try to use UART port to send AT command to change the usbcfg. Thanks!
We do not recommend you set it by yourself. Thanks!

I can’t use UART anymore, serial interfaces seems disabled.
Only wdm is active.

I need another way to unlock the device

How about debug UART port ? If still cannot use, you may try to upgrade the module firmware or change a new module to test. Thanks!

It seems there’s still one serial port alive, not one with the AT commands, don’t know if its debug (how could i verify this?).

I have an identical module, and works well.

Could I try to update/reload the firmware?
The device version is EC20EQAR02A13E2G.


Dear Abietre,
The module you used is quite old, now already EOL for a long time, so it is hard to reload the firmware in your side. It is better to change the new module and ask your supplier to reload it. Thanks!