Hello team and community,
After about a year of using the device i am very satisfied, although some days ago I could not use the device. It does not detect the USB modem and reboots every 30 seconds.
Within those 30 seconds timeframe I was able to upload latest stable firmware to the device and it updated, but this did not fix the problem. I also removed SIM cards I was using as suggested on other threads, but it did not help either.
Analysis file (before updating to latest firmware)
Device: Teltonika RUTM30, HW rev 0002, batch 0001
Firmware: RUTM_R_00.07.16.3 (released 2025-07-28), bootloader 2.15.6
Modem: built-in Quectel RG520N-EB, USB ID 2c7c:0801, USB path 2-1, 3 SIM slots
Modem firmware: RG520NEBDCR03A04M4G_01.200.01.200
Troubleshoot file captured: 2026-07-27 02:04 CEST
Modem absent at the USB layer
sysinfo.log — USB devices, only the two root hubs:
[USB DEVICES]
Bus 001 Device 001: ID 1d6b:0002
Bus 002 Device 001: ID 1d6b:0003
gsm.log:
"mdm_stats": { "num_modems": 0, "blocked_modems": [] }
kernel.log, [Device files] — no /dev/ttyUSB*, no /dev/cdc-wdm*, no /dev/modem_cmd. network.log — no wwan0, no qmimux0.
system.log dmesg — the xHCI controller and both root hubs initialise normally, and then nothing enumerates:
[ 7.479925] xhci-mtk 1e1c0000.xhci: Host supports USB 3.0 SuperSpeed
[ 7.505794] hub 2-0:1.0: USB hub found
[ 7.509731] hub 2-0:1.0: 1 port detected
There is no usb 2-1: new SuperSpeed USB device ... line anywhere in the boot log. On a healthy unit that line is what creates the modem.
Every dependent service therefore fails:
daemon.err mobifd: Failed to get information about modems
daemon.err urcd: Failed to get modems
daemon.err email_to_sms: Modem not found
daemon.err ntpclient[7726]: get_time_from_modem: 688 error: Failed to
get proper datetime from operator station: Not found
cloud_solutions.log: rms get_status: Command failed: Not found, wan_state: NO_WAN_LINK.
mctl performing the normal power-on pulse at preinit confirms the firmware did try to bring the module up:
kern.info kernel: mctl: writting '1' to /sys/class/gpio/modem_power/value
kern.info kernel: mctl: writting '0' to /sys/class/gpio/modem_power/value
Importantly, lsusb shows no :9008 device either. 2c7c:9008 or 05c6:9008 is what a Qualcomm module in EDL (emergency download) mode looks like. Teltonika support uses the presence of :9008 as the “still recoverable in software” marker.
The modem worked for about one minute after the storage period,
then vanished permanently
Reconstructed from log.db (NETWORK and SYSTEM tables). All times UTC; the device clock is unreliable, see 2.4.
| Time (UTC) | Event |
|---|---|
| 2026-04-08 19:26 | last normal activity before the device was stored |
| — | ~3.5 months unpowered, no log entries |
| 2026-07-26 16:38 → 16:45 | Mobile data disconnected (internal modem) repeating every ~23 s |
| 2026-07-26 16:46:48 | first Device startup after unexpected shutdown of the reboot loop |
| 2026-07-26 16:47:37 | Mobile data connected + Joined 5G-NSA network + Connected to operator |
| 2026-07-26 16:48:23 | Mobile data disconnected |
| 2026-07-26 17:03:01 | last modem-related event ever recorded |
| 2026-07-27 00:03:16 | last boot in the loop; modem absent from here on |
Troubleshoot file was exported from before the Firmware upgrade to latest stable one. But this did not fix anything. Still resets every 30-60 seconds, and no modem detected.
I have also reset device to factory settings.
Any help appreciated!