I have three Raspberry Pi 2 devices running up-to-date versions of Raspbian, identically configured with two identical 3G USB modems (ZTE D6601).On one of them, the modem is made available as a ttyUSB device upon startup and connecting it to the internet (using nmcli / Network-Manager) works fine. On the other, it is simply not. I have even re-set up both devices from scratch, interchanged the 3G modems but no success. The device codes as shown in lsusb are changed during startup using usb_modeswitch.This is what I am seeing when running lsusb and nmcli dev:Device 1 (ok):Device 2 (not ok):The dmesg outputs are:Device 1 (ok):[   27.705026] usb 1-1.4: new high-speed USB device number 5 using dwc_otg[   27.808010] usb 1-1.4: New USB device found, idVendor=19d2, idProduct=0108[   27.808040] usb 1-1.4: New USB device strings: Mfr=3, Product=2, SerialNumber=4[   27.808057] usb 1-1.4: Product: HSPA WCDMA Technologies MSM[   27.808073] usb 1-1.4: Manufacturer: HSPA,Incorporated[   27.808089] usb 1-1.4: SerialNumber: MF6670VIED010000[   27.814276] usb-storage 1-1.4:1.4: USB Mass Storage device detected[   27.814782] scsi host1: usb-storage 1-1.4:1.4[   28.000852] usbcore: registered new interface driver usbserial[   28.000985] usbcore: registered new interface driver usbserial_generic[   28.001105] usbserial: USB Serial support registered for generic[   28.069837] usbcore: registered new interface driver option[   28.070017] usbserial: USB Serial support registered for GSM modem (1-port)[   28.070618] option 1-1.4:1.0: GSM modem (1-port) converter detected[   28.071224] usb 1-1.4: GSM modem (1-port) converter now attached to ttyUSB0[   28.071564] option 1-1.4:1.1: GSM modem (1-port) converter detected[   28.072078] usb 1-1.4: GSM modem (1-port) converter now attached to ttyUSB1[   28.072407] option 1-1.4:1.2: GSM modem (1-port) converter detected[   28.072900] usb 1-1.4: GSM modem (1-port) converter now attached to ttyUSB2[   28.073217] option 1-1.4:1.3: GSM modem (1-port) converter detected[   28.073732] usb 1-1.4: GSM modem (1-port) converter now attached to ttyUSB3Device 2 (not ok):[   17.223150] usb 1-1.4: new high-speed USB device number 5 using dwc_otg[   17.326370] usb 1-1.4: New USB device found, idVendor=19d2, idProduct=0108[   17.326399] usb 1-1.4: New USB device strings: Mfr=3, Product=2, SerialNumber=4[   17.326417] usb 1-1.4: Product: HSPA WCDMA Technologies MSM[   17.326433] usb 1-1.4: Manufacturer: HSPA,Incorporated[   17.326449] usb 1-1.4: SerialNumber: MF6670VIED010000*Output stops after this*My actual question: Could any of you point me in a new direction of troubleshooting this, please?
3G USB modem recognized but no ttyUSBx device available. Works on one device, fails on 2
debian;usb;networkmanager;raspbian;3g