RUTM51 modem disconnects several times a day

kasperisager · March 27, 2025, 9:36pm

I have a recurring issue with a RUTM51 router that keeps disconnecting several times a day for a couple of minutes before coming back online. Here are the logs from the most recent case, though it’s always the same and seems to start with a USB disconnect:

17563 Thu Mar 27 19:08:44 2025 kern.info kernel: [357175.088386] usb 2-1: USB disconnect, device number 18
17564 Thu Mar 27 19:08:44 2025 kern.info kernel: [357175.093768] cdc_ncm 2-1:1.0 usb0: unregister 'cdc_ncm' usb-1e1c0000.xhci-1, CDC NCM
17565 Thu Mar 27 19:08:44 2025 daemon.notice odhcp6c[32352]: carrier => 0 event on
17566 Thu Mar 27 19:08:44 2025 daemon.notice odhcp6c[32352]: (re)starting transaction on usb0
17567 Thu Mar 27 19:08:44 2025 daemon.info odhcp6c[32352]: Interface usb0 sending router solicitation message
17568 Thu Mar 27 19:08:44 2025 daemon.notice netifd: Network device 'usb0' link is down
17569 Thu Mar 27 19:08:44 2025 daemon.notice netifd: Interface 'mob1s1a1_4' has link connectivity loss
17570 Thu Mar 27 19:08:44 2025 daemon.notice netifd: Interface 'mob1s1a1_6' has link connectivity loss
17571 Thu Mar 27 19:08:44 2025 kern.info kernel: [357175.379933] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
17572 Thu Mar 27 19:08:44 2025 kern.info kernel: [357175.388516] option 2-1:1.2: device disconnected
17573 Thu Mar 27 19:08:44 2025 kern.info kernel: [357175.393926] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
17574 Thu Mar 27 19:08:44 2025 kern.info kernel: [357175.402402] option 2-1:1.3: device disconnected
17575 Thu Mar 27 19:08:44 2025 kern.info kernel: [357175.468723] option1 ttyUSB2: GSM modem (1-port) converter now disconnected from ttyUSB2
17576 Thu Mar 27 19:08:44 2025 kern.info kernel: [357175.477150] option 2-1:1.4: device disconnected
17577 Thu Mar 27 19:08:44 2025 kern.info kernel: [357175.483267] option1 ttyUSB3: GSM modem (1-port) converter now disconnected from ttyUSB3
17578 Thu Mar 27 19:08:44 2025 kern.info kernel: [357175.491752] option 2-1:1.5: device disconnected
17579 Thu Mar 27 19:08:44 2025 kern.info kernel: [357175.497169] option1 ttyUSB4: GSM modem (1-port) converter now disconnected from ttyUSB4
17580 Thu Mar 27 19:08:44 2025 kern.info kernel: [357175.505637] option 2-1:1.6: device disconnected
17581 Thu Mar 27 19:08:44 2025 daemon.notice odhcp6c[32352]: Starting SOLICIT transaction (timeout 4294967295s, max rc 0)
17582 Thu Mar 27 19:08:44 2025 daemon.err odhcp6c[32352]: Failed to send SOLICIT message to ff02::1:2 (Network unreachable)
17583 Thu Mar 27 19:08:45 2025 daemon.notice netifd: Interface 'mob1s1a1_4' is disabled
17584 Thu Mar 27 19:08:45 2025 daemon.notice netifd: Interface 'mob1s1a1_6' is disabled
17585 Thu Mar 27 19:08:45 2025 daemon.notice netifd: Interface 'mob1s1a1_6' is now down
17586 Thu Mar 27 19:08:45 2025 daemon.info dnsmasq[15845]: reading /tmp/resolv.conf.d/resolv.conf.auto
17587 Thu Mar 27 19:08:45 2025 daemon.info dnsmasq[15845]: using nameserver 1.1.1.2#53
17588 Thu Mar 27 19:08:45 2025 daemon.info dnsmasq[15845]: using nameserver 1.0.0.2#53
17589 Thu Mar 27 19:08:45 2025 daemon.info dnsmasq[15845]: using nameserver 2606:4700:4700::1112#53
17590 Thu Mar 27 19:08:45 2025 daemon.info dnsmasq[15845]: using nameserver 2606:4700:4700::1002#53
17591 Thu Mar 27 19:08:45 2025 daemon.info dnsmasq[15845]: using nameserver 1.1.1.2#53
17592 Thu Mar 27 19:08:45 2025 daemon.info dnsmasq[15845]: using nameserver 1.0.0.2#53
17593 Thu Mar 27 19:08:45 2025 daemon.info dnsmasq[15845]: using nameserver 2606:4700:4700::1112#53
17594 Thu Mar 27 19:08:45 2025 daemon.info dnsmasq[15845]: using nameserver 2606:4700:4700::1002#53
17595 Thu Mar 27 19:08:45 2025 daemon.info dnsmasq[15845]: using only locally-known addresses for test
17596 Thu Mar 27 19:08:45 2025 daemon.info dnsmasq[15845]: using only locally-known addresses for onion
17597 Thu Mar 27 19:08:45 2025 daemon.info dnsmasq[15845]: using only locally-known addresses for localhost
17598 Thu Mar 27 19:08:45 2025 daemon.info dnsmasq[15845]: using only locally-known addresses for local
17599 Thu Mar 27 19:08:45 2025 daemon.info dnsmasq[15845]: using only locally-known addresses for invalid
17600 Thu Mar 27 19:08:45 2025 daemon.info dnsmasq[15845]: using only locally-known addresses for bind
17601 Thu Mar 27 19:08:45 2025 daemon.info dnsmasq[15845]: using only locally-known addresses for lan
17602 Thu Mar 27 19:08:45 2025 daemon.notice netifd: mob1s1a1_4 (32340): udhcpc: SIOCGIFINDEX: No such device
17603 Thu Mar 27 19:08:45 2025 daemon.notice netifd: mob1s1a1_4 (32340): udhcpc: received SIGTERM
17604 Thu Mar 27 19:08:45 2025 daemon.notice netifd: mob1s1a1_4 (32340): udhcpc: unicasting a release of 10.169.30.250 to 10.169.30.1
17605 Thu Mar 27 19:08:45 2025 daemon.notice netifd: mob1s1a1_4 (32340): udhcpc: sending release
17606 Thu Mar 27 19:08:45 2025 daemon.notice netifd: mob1s1a1_4 (32340): udhcpc: can't bind to interface usb0: No such device
17607 Thu Mar 27 19:08:45 2025 daemon.notice netifd: mob1s1a1_4 (32340): udhcpc: bindtodevice: No such device
17608 Thu Mar 27 19:08:45 2025 daemon.notice netifd: mob1s1a1_4 (32340): udhcpc: entering released state
17609 Thu Mar 27 19:08:45 2025 daemon.notice netifd: mob1s1a1_4 (32340): Command failed: Permission denied
17610 Thu Mar 27 19:08:45 2025 daemon.notice netifd: Interface 'mob1s1a1_4' is now down
17611 Thu Mar 27 19:08:46 2025 daemon.notice netifd: mob1s1a1 (26702): Stopping network mob1s1a1
17612 Thu Mar 27 19:08:46 2025 daemon.info gsmd[3143]: [__write:1300] warning: [CMM] Write to `2-1 [2c7c:0900]` modem failed: errno 5
17613 Thu Mar 27 19:08:46 2025 daemon.info gsmd[3143]: [common_write_handle:224] warning: [CMM] Failed to send command (0/13 bytes transferred) to `2-1 [2c7c:0900]` modem!
17614 Thu Mar 27 19:08:46 2025 kern.info Mobile data disconnected (internal modem)
17615 Thu Mar 27 19:08:46 2025 user.warn kernel: [357177.712551] [01-serial-symlink.sh] New device ttyUSB0 at /devices/platform/1e1c0000.xhci/usb2/2-1/2-1:1.2/ttyUSB0/tty/ttyUSB0 appeared!
17616 Thu Mar 27 19:08:47 2025 user.warn kernel: [357177.942030] [01-serial-symlink.sh] New device ttyUSB1 at /devices/platform/1e1c0000.xhci/usb2/2-1/2-1:1.3/ttyUSB1/tty/ttyUSB1 appeared!
17617 Thu Mar 27 19:08:47 2025 daemon.info gsmd[3143]: [__write:1300] warning: [CMM] Write to `2-1 [2c7c:0900]` modem failed: errno 5
17618 Thu Mar 27 19:08:47 2025 daemon.info gsmd[3143]: [common_write_handle:224] warning: [CMM] Failed to send command (0/13 bytes transferred) to `2-1 [2c7c:0900]` modem!
17619 Thu Mar 27 19:08:47 2025 user.warn kernel: [357178.187931] [01-serial-symlink.sh] New device ttyUSB2 at /devices/platform/1e1c0000.xhci/usb2/2-1/2-1:1.4/ttyUSB2/tty/ttyUSB2 appeared!
17620 Thu Mar 27 19:08:47 2025 user.warn kernel: [357178.548699] [01-serial-symlink.sh] New device ttyUSB3 at /devices/platform/1e1c0000.xhci/usb2/2-1/2-1:1.5/ttyUSB3/tty/ttyUSB3 appeared!
17621 Thu Mar 27 19:08:47 2025 user.warn kernel: [357178.830545] [01-serial-symlink.sh] New device ttyUSB4 at /devices/platform/1e1c0000.xhci/usb2/2-1/2-1:1.6/ttyUSB4/tty/ttyUSB4 appeared!
17622 Thu Mar 27 19:08:48 2025 daemon.info gsmd[3143]: [__write:1300] warning: [CMM] Write to `2-1 [2c7c:0900]` modem failed: errno 5
17623 Thu Mar 27 19:08:48 2025 daemon.info gsmd[3143]: [common_write_handle:224] warning: [CMM] Failed to send command (0/13 bytes transferred) to `2-1 [2c7c:0900]` modem!
17624 Thu Mar 27 19:08:49 2025 daemon.notice netifd: mob1s1a1 (26702): Command failed: Request timed out
17625 Thu Mar 27 19:08:49 2025 daemon.notice netifd: mob1s1a1 (26702): Command failed: Not found
17626 Thu Mar 27 19:08:49 2025 daemon.notice netifd: mob1s1a1 (26702): Command failed: Permission denied
17627 Thu Mar 27 19:08:49 2025 daemon.notice netifd: Interface 'mob1s1a1' is now down
17628 Thu Mar 27 19:08:49 2025 daemon.warn dnsmasq[15845]: no servers found in /tmp/resolv.conf.d/resolv.conf.auto, will retry
17629 Thu Mar 27 19:08:49 2025 daemon.info dnsmasq[15845]: read /etc/hosts - 12 names
17630 Thu Mar 27 19:08:49 2025 daemon.info dnsmasq[15845]: read /tmp/hosts/dhcp.cfg01411c - 2 names
17631 Thu Mar 27 19:08:49 2025 daemon.info dnsmasq-dhcp[15845]: read /etc/ethers - 0 addresses
17632 Thu Mar 27 19:08:49 2025 kern.info Mobile data disconnected (internal modem)
17633 Thu Mar 27 19:08:59 2025 kern.info kernel: [357190.528319] usb 2-1: new SuperSpeed Gen 1 USB device number 19 using xhci-mtk
17634 Thu Mar 27 19:08:59 2025 kern.info kernel: [357190.578969] cdc_ncm 2-1:1.0: MAC-Address: 0e:7b:ee:c2:21:a6
17635 Thu Mar 27 19:08:59 2025 kern.info kernel: [357190.586629] cdc_ncm 2-1:1.0 usb0: register 'cdc_ncm' at usb-1e1c0000.xhci-1, CDC NCM, 0e:7b:ee:c2:21:a6
17636 Thu Mar 27 19:08:59 2025 kern.info kernel: [357190.601724] option 2-1:1.2: GSM modem (1-port) converter detected
17637 Thu Mar 27 19:08:59 2025 kern.info kernel: [357190.609294] usb 2-1: GSM modem (1-port) converter now attached to ttyUSB0
17638 Thu Mar 27 19:08:59 2025 kern.info kernel: [357190.618761] option 2-1:1.3: GSM modem (1-port) converter detected
17639 Thu Mar 27 19:08:59 2025 kern.info kernel: [357190.625624] usb 2-1: GSM modem (1-port) converter now attached to ttyUSB1
17640 Thu Mar 27 19:08:59 2025 kern.info kernel: [357190.634646] option 2-1:1.4: GSM modem (1-port) converter detected
17641 Thu Mar 27 19:08:59 2025 kern.info kernel: [357190.642062] usb 2-1: GSM modem (1-port) converter now attached to ttyUSB2
17642 Thu Mar 27 19:08:59 2025 kern.info kernel: [357190.651041] option 2-1:1.5: GSM modem (1-port) converter detected
17643 Thu Mar 27 19:08:59 2025 kern.info kernel: [357190.657954] usb 2-1: GSM modem (1-port) converter now attached to ttyUSB3
17644 Thu Mar 27 19:08:59 2025 kern.info kernel: [357190.667047] option 2-1:1.6: GSM modem (1-port) converter detected
17645 Thu Mar 27 19:08:59 2025 kern.info kernel: [357190.674043] usb 2-1: GSM modem (1-port) converter now attached to ttyUSB4
17646 Thu Mar 27 19:09:00 2025 user.warn kernel: [357191.839386] [01-serial-symlink.sh] New device ttyUSB0 at /devices/platform/1e1c0000.xhci/usb2/2-1/2-1:1.2/ttyUSB0/tty/ttyUSB0 appeared!
17647 Thu Mar 27 19:09:01 2025 user.warn kernel: [357192.065089] [01-serial-symlink.sh] New device ttyUSB1 at /devices/platform/1e1c0000.xhci/usb2/2-1/2-1:1.3/ttyUSB1/tty/ttyUSB1 appeared!
17648 Thu Mar 27 19:09:01 2025 user.warn kernel: [357192.277514] [01-serial-symlink.sh] New device ttyUSB2 at /devices/platform/1e1c0000.xhci/usb2/2-1/2-1:1.4/ttyUSB2/tty/ttyUSB2 appeared!
17649 Thu Mar 27 19:09:01 2025 user.warn kernel: [357192.491650] [01-serial-symlink.sh] New device ttyUSB3 at /devices/platform/1e1c0000.xhci/usb2/2-1/2-1:1.5/ttyUSB3/tty/ttyUSB3 appeared!
17650 Thu Mar 27 19:09:01 2025 user.warn kernel: [357192.703591] [01-serial-symlink.sh] New device ttyUSB4 at /devices/platform/1e1c0000.xhci/usb2/2-1/2-1:1.6/ttyUSB4/tty/ttyUSB4 appeared!
17651 Thu Mar 27 19:09:07 2025 daemon.info gsmd[3143]: [ubus_notify_event:299] error: [MODEM_UBUS] Failed to send ubus notify for `2-1 [2c7c:0900]` modem!
17652 Thu Mar 27 19:09:07 2025 daemon.info mobifd: [gsm.modem0] Starting modem settings init
17653 Thu Mar 27 19:09:07 2025 daemon.err mobifd: [gsm.modem0] GSM error in "mb_generic_modem_cfun:1358" (Invalid response)
17654 Thu Mar 27 19:09:07 2025 daemon.err mobifd: [gsm.modem0] Failed to set CFUN: "2"(full)
17655 Thu Mar 27 19:09:07 2025 kern.info kernel: SIM state changed to not inserted (internal modem)
17656 Thu Mar 27 19:09:12 2025 daemon.info mobifd: [gsm.modem0] Config reload initiated
17657 Thu Mar 27 19:09:12 2025 kern.info kernel: SIM state changed to not inserted (internal modem)
17658 Thu Mar 27 19:09:15 2025 daemon.info mobifd: [gsm.modem0] Config reload initiated
17659 Thu Mar 27 19:09:21 2025 daemon.err mobifd: [gsm.modem0] GSM error in "mb_check_sms_storage:564" (Failed to parse response), gsmd_method_id: "63"
17660 Thu Mar 27 19:09:21 2025 daemon.err mobifd: [gsm.modem0] Failed to get SMS storage
17661 Thu Mar 27 19:09:24 2025 daemon.err mobifd: [gsm.modem0] Init 'sms_storage_check' failed. Retrying
17662 Thu Mar 27 19:09:24 2025 daemon.err mobifd: [gsm.modem0] GSM error in "mb_check_sms_storage:564" (Failed to parse response), gsmd_method_id: "63"
17663 Thu Mar 27 19:09:24 2025 daemon.err mobifd: [gsm.modem0] Failed to get SMS storage
17664 Thu Mar 27 19:09:27 2025 daemon.err mobifd: [gsm.modem0] Init 'sms_storage_check' failed. Retrying
17665 Thu Mar 27 19:09:27 2025 daemon.err mobifd: [gsm.modem0] GSM error in "mb_check_sms_storage:564" (Failed to parse response), gsmd_method_id: "63"
17666 Thu Mar 27 19:09:27 2025 daemon.err mobifd: [gsm.modem0] Failed to get SMS storage
17667 Thu Mar 27 19:09:30 2025 daemon.err mobifd: [gsm.modem0] Init 'sms_storage_check' failed. Retrying
17668 Thu Mar 27 19:09:37 2025 daemon.info mobifd: [gsm.modem0] Modem settings init completed
17669 Thu Mar 27 19:09:37 2025 daemon.info mobifd: [gsm.modem0] Starting connection setup
17670 Thu Mar 27 19:09:37 2025 daemon.info mobifd: [gsm.modem0] Attempting to establish connection to operator with "30s" of timeout
17671 Thu Mar 27 19:09:42 2025 daemon.info mobifd: [gsm.modem0] Connected to operator "23806"
17672 Thu Mar 27 19:09:43 2025 daemon.info mobifd: [gsm.modem0] -CFUN- Functionality: "Full"
17673 Thu Mar 27 19:09:43 2025 daemon.info mobifd: [gsm.modem0] -COPS- Mode: "Auto", operator: "23806"
17674 Thu Mar 27 19:09:43 2025 daemon.info mobifd: [gsm.modem0] -CREG- Mode: "Enabled (with location information)", status: "Not registered", LAC: "", cell ID: "", technology: "Unknown"
17675 Thu Mar 27 19:09:43 2025 daemon.info mobifd: [gsm.modem0] -CGREG- Mode: "Enabled (with location information)", status: "Not registered", LAC: "", cell ID: "", technology: "Unknown"
17676 Thu Mar 27 19:09:43 2025 daemon.info mobifd: [gsm.modem0] -CEREG- Mode: "Enabled (with location information)", status: "Registered, home", LAC: "", cell ID: "58136125", technology: "E-UTRAN-NR"
17677 Thu Mar 27 19:09:43 2025 daemon.info mobifd: [gsm.modem0] -C5GREG- Mode: "Enabled (with location information)", status: "Not registered", LAC: "", cell ID: "", technology: "Unknown"
17678 Thu Mar 27 19:09:43 2025 daemon.info mobifd: [gsm.modem0] IP address on PDP context "1": "10.213.245.164"
17679 Thu Mar 27 19:09:43 2025 daemon.notice netifd: Interface 'mob1s1a1' is setting up now
17680 Thu Mar 27 19:09:43 2025 daemon.notice netifd: mob1s1a1 (28094): wwan[28094] Using wwan usb device on bus 2-1
17681 Thu Mar 27 19:09:43 2025 daemon.notice netifd: mob1s1a1 (28094): wwan[28094] Using proto:cdc_ncm device:/dev/ttyUSB0 iface:usb0 desc:Quectel RG500U
17682 Thu Mar 27 19:09:44 2025 daemon.notice netifd: mob1s1a1 (28094): Connection setup for mob1s1a1 starting!
17683 Thu Mar 27 19:09:44 2025 daemon.notice netifd: mob1s1a1 (28094): Activating PDP CID1!
17684 Thu Mar 27 19:09:46 2025 daemon.notice netifd: mob1s1a1 (28094): Starting setup data call!
17685 Thu Mar 27 19:09:46 2025 daemon.notice netifd: mob1s1a1 (28094): Setting MTU: 1500 on usb0
17686 Thu Mar 27 19:09:46 2025 daemon.notice netifd: Interface 'mob1s1a1' is now up

Is there something I can do to further diagnose the cause or could it be a hardware fault? Thanks in advance!

Martynas · March 28, 2025, 10:49am

Hello,

Thank you for sharing the logs and providing details regarding the issue with constant modem disconnections. To troubleshoot and understand the cause of the recurring disconnections more precisely, we will need to contact you privately.

A form for submitting further details has been sent to the email address you used to register on the forum. When filling out the form, please use 13014 as the ticket ID. Once you’ve submitted the form, we will reach out to you via email to investigate the matter more
effectively.

Kind regards,

WilcodeGroot · March 28, 2025, 1:37pm

I have a similar problem.
going through all settings I found the there was a ping every 15 minutes which what each time just before the connection was broken.
Disabling this ping solved part of the problem, but still there is a a connection problem during the day:
Between 0600 and 0630 h the connection with broken for some lan’s and it comes back between 2000 and 2030 h.
It looks like only on some instruments on the lan.

kasperisager · March 29, 2025, 9:59pm

I updated the firmware to RUTM_R_00.07.13.3 today and unlike with previous updates did not do a manual tailscale update to update the Tailscale VPN, which I’m running on all my devices, to the latest version. I’ve just checked the logs and there has been no disconnects today since updating the firmware and leaving Tailscale at 1.70.0-5. I’ll continue to monitor.

kasperisager · March 30, 2025, 8:20am

It disconnected once overnight so I’m retracting my suspicions of Tailscale for now at least.

kasperisager · April 1, 2025, 5:28pm

This seems like a common issue over the last few weeks across several devices:

I still haven’t found anything interesting on my end, my last attempt being disabling fast transition after seeing some OpenWRT threads about possible rekeying issues and noticing rekeying failures in the logs at the time of the disconnects.

kasperisager · April 5, 2025, 8:04am

Since April 2 I’ve only had a single disconnect. I updated to RUTM_R_00.07.13.4 yesterday and will continue monitoring.

kasperisager · April 5, 2025, 4:05pm

I just had another disconnect so the issue is still present.

Martynas · April 7, 2025, 6:35am

Hello @kasperisager,

Thank you for the update. Since the issue still persists, we’d like to continue the investigation privately to troubleshoot more effectively.

I’ve seen that the form previously sent to you was successfully submitted, and you should have received an email from us. Could we kindly ask to continue the conversation there, as we need to gather some sensitive information that isn’t suitable for public sharing?

Best regards,

kasperisager · April 7, 2025, 2:09pm

@Martynas Could you verify that the troubleshoot files have been received on your end? I’ve sent several over the past couple of weeks as I’ve encountered disconnects and have followed up today with the most recent one.

Martynas · April 8, 2025, 5:23am

Hello @kasperisager,

Yes, I can confirm that we finally received the troubleshoot file from you yesterday. Just to double-check—did you press Reply on our previous email when sending earlier messages? It seems we weren’t receiving your replies before, but now everything is coming through properly. Since we can now receive your emails and attachments, we’ll continue troubleshooting and communication via email going forward.

Thank you for your patience, and apologies for the confusion.

Best regards,

kasperisager · April 11, 2025, 7:00am

No worries at all!

For posterity, this turned out to be a known issue with the modem firmware with a fix pending from the manufacturer. A separate but related issue was that I had trouble actually updating the modem firmware to the latest version both using the online installer and from a USB drive. Teltonika helpfully provided a patched firmware release that did the trick.

I’ll mark this comment as the solution for visibility.

system · April 13, 2025, 7:01pm

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