Please note that these directions are applicable to TPE-EM7455CHIP and TPE-USB4GLTE modems from ThinkPenguin, Inc that utilize an EM7455 chip. The directions may not work for modems with these chips acquired elsewhere.
Boot from a live Linux Mint 21.3 Edge flash drive and run:
To unbrick an EM7455 modem that doesn't give you /dev/ttyUSB2 open a terminal and run:
sudo modprobe qcserial
sudo modprobe qmi_wwan
Then plug the modem into a USB 2.0 port.
dmesg should report:
[ 241.466908] usbcore: registered new interface driver usbserial_generic
[ 241.466922] usbserial: USB Serial support registered for generic
[ 241.473224] usbcore: registered new interface driver qcserial
[ 241.473237] usbserial: USB Serial support registered for Qualcomm USB modem
[ 241.491273] usbcore: registered new interface driver cdc_wdm
[ 241.493549] usbcore: registered new interface driver qmi_wwan
[ 286.032631] usb 1-5: new high-speed USB device number 6 using xhci_hcd
[ 286.182158] usb 1-5: config 1 has an invalid interface number: 8 but max is 3
[ 286.182169] usb 1-5: config 1 has no interface number 1
[ 286.182877] usb 1-5: New USB device found, idVendor=413c, idProduct=81b6, bcdDevice= 0.06
[ 286.182884] usb 1-5: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 286.182887] usb 1-5: Product: DW5811e Snapdragon™ X7 LTE
[ 286.182890] usb 1-5: Manufacturer: Sierra Wireless, Incorporated
[ 286.182893] usb 1-5: SerialNumber: LF01203920193019203
[ 286.190916] qcserial 1-5:1.0: Qualcomm USB modem converter detected
[ 286.191179] usb 1-5: Qualcomm USB modem converter now attached to ttyUSB0
[ 286.192281] qcserial 1-5:1.2: Qualcomm USB modem converter detected
[ 286.192483] usb 1-5: Qualcomm USB modem converter now attached to ttyUSB1
[ 286.193417] qcserial 1-5:1.3: Qualcomm USB modem converter detected
[ 286.193598] usb 1-5: Qualcomm USB modem converter now attached to ttyUSB2
[ 286.194669] qmi_wwan 1-5:1.8: cdc-wdm0: USB WDM device
[ 286.194827] wwan wwan0: port wwan0qmi0 attached
[ 286.195520] qmi_wwan 1-5:1.8 wwan0: register 'qmi_wwan' at usb-0000:00:14.0-5, WWAN/QMI device, f4:33:41:44:4f:e4
Then run:
sudo apt install minicom
sudo minicom -D /dev/ttyUSB2
ATE1
AT!ENTERCND="A710"
AT!USBCOMP=1,1,100D
AT!RESET
Unplug the modme and plug it back in.
Then follow the instructions on updating the firmware and unlocking the modem:
https://www.thinkpenguin.com/gnu-linux/make-em7455-work-gnulinux-2024-ed...