Are you sure that usb_modeswitch hasn't run already after you inserted the device?
Check the output of "dmesg" repeatedly immediately after plug in.

As for the interfaces created, the information in this thread applies. You won't get ttyUSBx but ttyHSx, provided that the "hso" driver module is ...

Hmm, power issues would have been my #1 hypothesis.

If the stick has no defects - I assume you have used it previously with no issues - then the focus is on the host system. Can you specify it?

Or puting a 41-zte_mf79n.rules files in /lib/udev/rules.d/ would be sufficiant to let usb_modeswitch read these rules.


Your initial device ID should already be included in the rules file of your usb_modeswitch package - unless it's seriously outdated.

# ZTE MF668 (Variant), MF70
ATTR{idVendor ...

I can see that you have set "DisableSwitching" in the global config file. That results in the usb-modeswitch automatism doing exactly nothing .
Also, there is no point in putting device-specific data into the global configuration file. It will be ignored. (I think the "device_reference" file may be ...

Some of your descriptions point to a hardware-related problem. I suspect it might be power-related.

Did you ever try with a powered USB hub between the Raspi and the dongle? This would show if a stable power source could make the problem go away.
USB dongles are allowed to draw 500 mA, some ...

What is your specific Linux distribution?

There should be no sniffing required. All current Linux distributions carry usb_modeswitch nowadays, and the E3372 has long been known and supported.
Which Linux distribution do you have installed on your computer?

I need to see the modem information.

Try switching on USB logging in the configuration. Then connect your modem, wait a moment, and then open the USB log, again from the configuration page.

Post the entire USB log here (as text please, not as a photo).

Debian should include a working installation of usb_modeswitch. If you encounter problems with a modem, switch on logging as described here:
https://www.draisberghof.de/usb_modeswitch/#trouble

Can you try again with the latest update?

There were some changes with the initial checks.

Can you launch the "su" tool in a terminal app?

You need to tell me which system you are using.

Most Linux distributions have usb_modeswitch included and ready to run.

Just place the widget on a workspace and touch "Configure".

If you have problems even before the operating system loads, you might want to look into the BIOS settings. I'd disable any options to boot from USB, if that's possible.