Hello,
Please try to perform the following procedure with your TRB device:
1. Turn off/unplug TRB140
2. Press and hold reset button, at the same time plug the power cable and keep holding reset button for about 5 seconds (mobile signal LED's should start blinking)
3. Download "ADB software" and "rootfs.ubi" file from here:
https://kaunas.teltonika.lt:444/f/a9ffe2e9d98446f2aaf3/?dl=1
4. Install ADB software
5. Place rootfs.ubi file in any easily accessible directory (e.g. in "C:\Test")
6. Open CMD ("Command Prompt" window) with administrator rights
7. Use cd command to navigate to the place where you saved the rootfs.ubi file (Example: cd C:\Test)
8. Then use this command: fastboot flash rootfs_a rootfs.ubi
9. When it completes, use this command: fastboot flash rootfs_b rootfs.ubi
10. When both commands are executed and finished running, unplug power from TRB and plug it again. It should boot up as normal
11. Install intermediate firmware version, which can be downloaded from here:
https://wiki.teltonika-networks.com/view/TRB140_Legacy_FW_Upgrade_Instructions
12. Install desired firmware version to TRB through WebUI. Lastest firmware can be downloaded from here:
https://wiki.teltonika-networks.com/view/TRB140_Firmware_Downloads
Best regards,