EM7455 stuck with no tty nor cdc-wdm devices

IoT Modules
1

Hello,
I got a EM7455 on an M2 adapter in a housing, and managed to update it with SWI9X30C_02.38.00.00.cwe and SWI9X30C_02.38.00.00_GENERIC_002.082_000.nvu. Initially it was showing this:

OK 
AT!ENTERCND="A710" 
OK 
? 
DW5811e Snapdragon™ X7 LTE 
 
OK 
AT!USBPID? 
!USBPID: 
APP : 81B6 
BOOT: 81B5 
 
OK 
AT!USBPRODUCT? 
DW5811e Snapdragon™ X7 LTE 
 
OK 
AT!PRIID? 
PRI Part Number: 9907260 
Revision: 001.000 
Customer: Dell 
 
Carrier PRI: 9999999_9904609_SWI9X30C_02.38.00.00_00_GENERIC_0AT+GMI 
Sierra Wireless, Incorporated

Then ran

AT!USBPID=81B6,81B5
AT!USBPRODUCT="Dell Wireless 5811e Gobi(TM)4G LTE Mobile Broadband Card"
AT!PRIID="9904609","002.026","DELL"

Did not run AT!RESET. Now when the device is connected over USB, it doesn’t create any TTY or CDC interfaces, and this is only printed in dmesg:

usb 1-3: new high-speed USB device number 19 using xhci_hcd
usb 1-3: config 1 has an invalid interface number: 8 but max is 3
usb 1-3: config 1 has no interface number 1
usb 1-3: New USB device found, idVendor=1199, idProduct=81b6, bcdDevice= 0.06
usb 1-3: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 1-3: Product: EM7455
usb 1-3: Manufacturer: Sierra Wireless, Incorporated
usb 1-3: SerialNumber: LFXXXXXXXXXXXXXX

Ubuntu 22.04, kernel 6.1, the Gobi DKMS drivers do not compile for me. Is there anything I can do to make the card reset to a default profile?

2

see if this helps:

3

Thanks for the hint, but alas - tried a few different driver versions under WIn10, and always getting an unrecognized device em7455 (actually 4 of them). Also, none of the generic windows drivers was accepting a parameter of DisableUsbCompAutoUpdate. Maybe it’s just Windows disliking me, or I’ve spent too long away from it. I guess I might be tossing that one in the bin.

4

Boot your Ubuntu 22.04. Don’t mess with any out-of-tree drivers. Just load option, configure it to handle the weird VID/PID you’ve got, connect to the correct /dev/ttyUSBx device and fixup the AT!USBPID and AT!USBVID mess.

Something along

modprobe option
echo 1199 81b6 > /sys/bus/usb-serial/drivers/option1/new_id
minicom /dev/ttyUSB3

Note that the AT speaking serial port could be on any of the /dev/ttyUSBx devices. You’ll just have to try them until you hit the right one.

Make sure you choose a valid VID+PID combination this time…