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thisJade

Member

Registered: 2026-04-26

Posts: 6

USB LTE Modem crashes after suspending and/or switching locations.

So I have no idea what to do anymore. I have a ThinkPad X13 Gen 4 with a Quectel Wireless Solutions Co., Ltd. EM05-G LTE Modem. It does work okayish (what you expect from a USB2 connection).
But after a random amount of suspending the ModemManager cant find the modem anymore.
Also if I suspend and then switch locations (as you do with a laptop) the ModemManager cant find the modem anymore.

(also but unrelated every time I suspend and wake the modem gets a new id in the modemmanager it usually goes up to 8 before dying)

At best I would like the modem to always stay on and always stay connected so that when I open the laptop it is already connected and also it doesnt die from randomly teleporting a few (hundred) kilometers.

Does anyone have any idea what I could try?

here the modemmanager (when its working):

  ----------------------------------
  General  |                   path: /org/freedesktop/ModemManager1/Modem/10
           |              device id: 45deee81f416644e110cb922eb7cab6824aeee21
  ----------------------------------
  Hardware |           manufacturer: Quectel
           |                  model: EM05-G
           |      firmware revision: EM05GFAR07A03M1G
           |           h/w revision: QUECTEL Mobile Broadband Modul
           |              supported: gsm-umts, lte
           |                current: gsm-umts, lte
           |           equipment id: (redacted)
  ----------------------------------
  System   |                 device: /sys/devices/pci0000:00/0000:00:08.1/0000:c3:00.3/usb5/5-4
           |                physdev: /sys/devices/pci0000:00/0000:00:08.1/0000:c3:00.3/usb5/5-4
           |                drivers: option, cdc_mbim
           |                 plugin: quectel
           |           primary port: cdc-wdm0
           |                  ports: cdc-wdm0 (mbim), ttyUSB1 (at), wwp195s0f3u4 (net)
  ----------------------------------
  Numbers  |                    own: (redacted)
  ----------------------------------
  Status   |                   lock: sim-pin2
           |         unlock retries: sim-pin2 (3)
           |                  state: connected
           |            power state: on
           |            access tech: lte
           |         signal quality: 16% (recent)
  ----------------------------------
  Modes    |              supported: allowed: 3g, 4g; preferred: none
           |                current: allowed: 3g, 4g; preferred: none
  ----------------------------------
  IP       |              supported: ipv4, ipv6, ipv4v6
  ----------------------------------
  3GPP     |                   imei: (redacted)
           |          enabled locks: fixed-dialing
           |            operator id: (redacted)
           |          operator name: (redacted)
           |           registration: home
           |   packet service state: attached
  ----------------------------------
  3GPP EPS |   ue mode of operation: csps-2
           | initial bearer ip type: ipv4v6
  ----------------------------------
  SIM      |       primary sim path: /org/freedesktop/ModemManager1/SIM/10
           |         sim slot paths: slot 1: /org/freedesktop/ModemManager1/SIM/10 (active)
           |                         slot 2: /org/freedesktop/ModemManager1/SIM/11
  ----------------------------------
  Bearer   |                  paths: /org/freedesktop/ModemManager1/Bearer/0

otherwise it just says
couldnt find modem

seth

Member

From: Won't reply 2 private help req

Registered: 2012-09-03

Posts: 78,496

Re: USB LTE Modem crashes after suspending and/or switching locations.

Please post the complete journal for a boot where you lost the modem, eg

sudo journalctl -b -1 | nc termbin.com 9999

for the previous (-1) boot.

But before that

the ModemManager cant find the modem anymore

Assuming the device is actually still registered on the system - have you tried to restart ModemManager to see whether that's just a bug there?

At best I would like the modem to always stay on and always stay connected so that

… your battery will be drained in 3h sleep - this would in any event require hardware/firmware support to constantly feed power to the device and has nothing to do w/ the OS

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