TRB140 Failed Firmware Downgrade and Bricked


We use many TRB140s. When we receive a new one, we have a script which operates over SSH and loads them all to a known firmware version and then configures them using uci commands.

Whilst we may have a slightly older firmware version, we do not operate on the public internet so having all the latest CVE fixes is not a concern. It is more important for all modems to have the same firmware version as once they are deployed upgrading them is not really an option.

This process has been working well for several years until today. The firmware load portion of the script failed as follows:

Connecting to TRB140 at IP with default password
Connected to TRB140
Using latest locally cached firmware TRB1_R_00.07.02.7
> uci show system.system.device_fw_version
Firmware on device is version TRB1_R_00.07.03.4.
Transferring C:\Users\xxx\.cache\TRB1_R_00.07.02.7_WEBUI.bin to TRB140 /tmp/TRB1_R_00.07.02.7_WEBUI.bin
  [####################################]  100%          done
Running firmware update command on TRB140...
> sysupgrade /tmp/TRB1_R_00.07.02.7_WEBUI.bin
ERROR: Tue Feb  7 12:54:00 UTC 2023 upgrade: TRB1_R_00.07.02.7!
ERROR: Mods found: motorcomm_phy trb143!
ERROR: find: /greengrass/certs/: No such file or directory!
ERROR: find: /greengrass/certs/: No such file or directory!
ERROR: find: /etc/hostapd/: No such file or directory!
ERROR: Tue Feb  7 12:54:04 UTC 2023 upgrade: Saving config files...!
ERROR: Tue Feb  7 12:54:04 UTC 2023 upgrade: Commencing upgrade. Closing all shell sessions.!

Normally the firmware is an upgrade, but today it seems it was a downgrade as the new device had a newer version TRB1_R_00.07.03.4 than the version we tried to load TRB1_R_00.07.02.7. The ERRORs are a concern as it seems to allow you to perform this downgrade but then it fails, possibly part way through the process.

Following this the device has been power cycled, reset and also factory reset as per TRB140 Device Recovery Options - Teltonika Networks Wiki but alas can no longer ping the device on and fear that it is bricked.


  1. Should a downgrade such as this be expected to work or should it be avoided?
  2. Is there a way to un-brick this device?



Your TRB most likely can be recovered using fastboot, but it’s quite an involved process: TRB141 Device Not Accessible After Firmware Upgrade - Crowd Support Forum | Teltonika Networks
The updated file download can be found here: Sign in to your account
Please ignore the .ubi file within the 7z archive, use the one in the main folder.
However, you most likely will not be able to downgrade the firmware, as there has been a hardware change in TRB140, and the older firmware does not support the new hardware. I’d consider moving to 07.03.4 or newer versions.

Best regards,

Follow up questions:

  1. For modems that have the older hardware (from 2021), can we update them to the latest firmware?
  2. Is their a mailing list or similar I can subscribe to for announcements of hardware and firmware changes to the TRB140?


Yes, newer firmware supports older hardware.

We publish PCNs for all devices. For TRB140, it’s available here: TRB140 Product Change Notifications - Teltonika Networks Wiki
I believe the particular change in question is this: TRB140 Product Change Notifications - Teltonika Networks Wiki
However, 07.02.7 should still be supported. Once the device is recovered, could you try installing 07.02.7 using the WebUI and not the CLI? Generally, if there are hardware compatibility issues both the WebUI and the sysupgrade should not let you downgrade the device. Here is an example with the TRB245: Error uploading firmware for TRB245 - Crowd Support Forum | Teltonika Networks

Best regards,

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