RUT200/240 Devices Stuck on 2G – SIM or Firmware Issue?

NETWORKING SOLUTIONS
1

Hi,

We experienced an issue affecting approximately 40 RUT200/240 devices on 2025-05-20 at around 23:30 (UTC+1). At that time, all affected units lost connection to the mobile network simultaneously. While a few devices reconnected automatically after about an hour, most remained stuck in a state where they were searching for a 2G connection.

Our SIM cards are configured to support 4G only, so these devices were unable to reconnect while stuck on 2G. I was able to resolve the issue by manually setting the Mobile Connection Mode from Auto (4G/3G/2G) to 4G Only.

Could you help us determine:

  1. Whether this issue was caused by a temporary problem or policy change on the SIM provider’s end?
  2. Or if this could be related to recent firmware or modem behavior changes on the Teltonika side?

Any insights or logs we should check would be appreciated.

3

Good afternoon,

The most plausible cause is a temporary network provider issue or policy change that caused the devices to lose 4G connectivity and attempt to connect to 2G, which was unsupported by the SIM cards.
There is no clear evidence pointing to a recent firmware or modem behavior change causing this problem.
You may want to check with your SIM provider for any network events or policy changes around 2025-05-20 that could explain the outage. Meanwhile, ensuring your devices run the latest firmware versions and configuring Mobile Connection Mode to 4G Only can help mitigate similar issues.

Regards,
Arturas