Bug Quectel EC25-EUX answering to pings without the OS being turned on

I’m creating this topic to share with you a problem we’ve noticed on our routers/PCs which have a Quectel EC25-EUX network card. We use these cards to connect to the internet using the PPP protocol on the host, however the machine responds to pings even before the operating system starts, even when we are just in the bootloader. It is enough that the machine is powered to observe this behavior. This behavior being very troublesome, do you have a solution to this problem?

You can try to send AT+CFUN=0 before your system is loaded, and send AT+CFUN=1 after the system is up, so that the module can reload the network, thank you.


We use the QUECTEL EC25-EUX card in the following way.

The PC is powered on.
Then the BIOS initialize the PC
The Operating System bootloader starts
Then the Operating System (OpenBSD 7.1) starts
Once started the Operating System dialog with the QUECTEL EC25-EUX using a chat script:
using required AT / Hayes commands.
The PPPD daemon is then started to establish the IP connexion.

Until here everything works fine: the machine can be pinged via the SIM card associated IP address.

Then when the Operating System is halted: Strange things starts to appear here.
The IP of the SIM card is still responding for ping request while the OS is halted.

Then we power off the PC (unplugging the power supply) and ping request no longer have pong responses.

When we power on the machine (pluggin on the power supply) and as soon as the bios started and emitted a beep the IP is responding again to the ping quest while neither the bootloader nor the Operating System is started.

Conclusion: the Quectel EC25-EUX card respond to ping request at the pc early boot while
the Operating System is not started.

This is an anormal behavior: how can it be fixed ?