[MC7455] Unable to connect to LTE network

[giannisk]

Hi,

I have issue connecting to an LTE network. It seems that the modem can not detect any.
Some debug information that may help.

Kernel: Linux — 3.16.0-4-amd64 #1 SMP Debian 3.16.43-2 (2017-04-30) x86_64 GNU/Linux

Dmsg:
[16609.824322] usb 2-1.5: new high-speed USB device number 10 using ehci-pci
[16609.918040] usb 2-1.5: config 1 has an invalid interface number: 8 but max is 4
[16609.918050] usb 2-1.5: config 1 has an invalid interface number: 10 but max is 4
[16609.918055] usb 2-1.5: config 1 has no interface number 1
[16609.918059] usb 2-1.5: config 1 has no interface number 4
[16609.919116] usb 2-1.5: New USB device found, idVendor=1199, idProduct=9071
[16609.919125] usb 2-1.5: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[16609.919131] usb 2-1.5: Product: Sierra Wireless MC7455 Qualcomm® Snapdragon™ X7 LTE-A
[16609.919135] usb 2-1.5: Manufacturer: Sierra Wireless, Incorporated
[16609.919139] usb 2-1.5: SerialNumber: LQ71044854041020
[16609.920803] GobiSerial 2-1.5:1.0: GobiSerial converter detected
[16609.921151] usb 2-1.5: GobiSerial converter now attached to ttyUSB0
[16609.921966] GobiSerial 2-1.5:1.2: GobiSerial converter detected
[16609.922327] usb 2-1.5: GobiSerial converter now attached to ttyUSB1
[16609.923183] GobiSerial 2-1.5:1.3: GobiSerial converter detected
[16609.923486] usb 2-1.5: GobiSerial converter now attached to ttyUSB2
[16609.924439] GobiNet 2-1.5:1.8 eth4: register ‘GobiNet’ at usb-0000:00:1d.0-1.5, GobiNet Ethernet Device, HIDDEN
[16609.924814] USB Speed : USB 2.0
[16609.925748] GobiNet 2-1.5:1.10 eth5: register ‘GobiNet’ at usb-0000:00:1d.0-1.5, GobiNet Ethernet Device, HIDDEN

at!gstatus?
!GSTATUS:
Current Time: 574 Temperature: 52
Reset Counter: 3 Mode: LOW POWER MODE

OK

AT!IMPREF?
!IMPREF:
preferred fw version: 02.24.03.00
preferred carrier name: ?
preferred config name: ???
current fw version: 02.24.03.00
current carrier name: GENERIC
current config name: GENERIC_002.017_000

carrier name mismatch
config name mismatch

OK

Please let me know if you need any other information.

[dl5162]

Try

AT!IMPREF="GENERIC"
AT!RESET

[giannisk]

Hi dl5162,
It worked. Thank you very much. Can you explain why it was necessary to do so?

[dl5162]

@giannisk

Hi dl5162,
It worked. Thank you very much. Can you explain why it was necessary to do so?

Your AT!IMPREF? output showed

carrier name mismatch
config name mismatch

which was the reason for the low power mode. The preferred carrier and config names looked like wildcard(?) values. The “mismatch” result clearly showed that this did not work. All you had to do to fix it was to set the preferred values to your current values since those looked good.

But if you wanted to know why the modem ended up in this state, then I have no explanation. Maybe a firmware upgrade attempt with some weird input? I have no idea. I know you can configure these settings to anything using QMI requests, but most people don’t do that directly. They use a firmware upgrade tool, which hopefully provides some sane input to the modem.

[giannisk]

Thank you very much!

[zahmed]

Hi guys,
I recently bought sierra wireless MC7455 but our system is not recognizing this device. MC7345 module used to work well. I am suing PCIe slot to connect MC7455 but device manager shows no sierra wireless card as detected. Is it a compatibility issue?

[getzk004]

I had a similar problem where the firmware version between preferred and current were mismatched. In my case the carrier name was not missing but the versions were different and the current version was below the preferred. We did attempt a firmware upgrade on this machine and it has not been able to complete activation requests since then.

After completing the commands to set the impref to the correct carrier and resetting my EM7455 modem fired right up and activated like expected.

Thanks for the info!