I accidently changed the Device PID to 683E (same issue here). I can’t execute AT commands on the unique serial port available (/dev/ttyUSB0, the USB driver is in drivers/usb/serial/sierra.c)…
How can I change the module back to Direct IP mode?
I tried with gsmmux on /dev/ttyUSB0, but it fails to setup the virtual com.
I dont know if it can help. I noticed some data on the serial port, I can see this frame : 0x7e, 0x00, 0x09, …, 0x7e