EC200U mPCIe: can't set up an automatic connection after a reboot and configure ECM on Linux


I’ve been struggling for several days trying to configure the Quectel EC200U mPCIE module. I have the module connected to an RPi4 compute-module running a Debian distribution, and my goal is to set up ECM over the usb0 interface.

I’ve already managed to set up the module, connect to a network operator, obtain an IP, and ping the Google DNS. However, I’m encountering two problems:

  • On the RPi4 compute-module, when I run the command ifconfig -a in the terminal, I can see the usb0 interface but don’t see any IP address.

  • When I turn off the Quectel module and then turn it on again, the module fails to automatically establish a network connection.

Here are the troubleshooting steps I’ve performed:

  1. Check signal quality
    Result: +CSQ: 31,99 (31 is the highest possible value and indicates excellent signal quality. 99 means that the bit error rate is not reported, but from what I researched, it is not critical for the connection to an operator)
  2. Checked for available operators:
    Result: +COPS: (2,“MEO”,“MEO”,“26806”,7),(1,“vodafone P”,“voda P”,“26801”,7),(1,“NOS”,“NOS”,“26803”,7),(1,“MEO”,“MEO”,“26806”,0),(1,“vodafone P”,“voda P”,“26801”,0),(1,“NOS”,“NOS”,“26803”,0),(0-4),(0-2)
  3. Forced automatic registration to an operator:
    Result: +CME ERROR: 32 (Network error timeout indicating that the module could not complete the registration process to a network)

The question remains: If the received signal quality is maximum, if there are available operators, and if the module is configured to register automatically, why is it not succeeding? Only after the following process was I able to re-establish a connection, obtain an IP, and ping

  1. Reset the module to default settings
  2. Reboot:
  3. Configure USB Network Port Protocol (Use 1 for ECM protocol) and reboot
  4. Configured the module for automatic operator registration
  5. Checked the registration status:
    Result: +CREG: 1, 5 (1 means it is registered (home network) and 5 means it is roaming)
  6. Set the PDP context again:
  7. Activated the context:
  8. Successfully checked the IP:
    Result: +CGPADDR: 1,“”
  9. Successfully pinged Google’s DNS:
  10. Saved all configurations:

Once again, I was able to establish a connection, obtain an IP, and ping successfully. However, on the compute-module when using ifconfig -a, I still don’t get an IP on the usb0 interface. And if I turn the module off and on again, I once again fail to automatically obtain a connection.

If I check the registration status with AT+CREG? I get +CREG: 1,2 which means the module is enabled to register but is searching for an operator to register with.

Is this type of issue common and does Quectel have a procedure to solve it?

NOTE: More info to help the troubleshooting in comments.

I suppose you forgot to dial with +qnetdevctl