Hello gv,
Thank you for your question.
Now, for FMB920 devices we are using the newest base firmware 03.25.15.Rev.01. Please try to update it and check if you will have the same issue.
We would like to inform you that we do not share firmware files / updater and other files in community forum. To receive firmware files, updater and documentation on devices, please contact your Sales manager.
Best regards,
Teltonika Support