This post it to help other people avoid the hours that I have wasted. The RUT manual pages describe a Bootloader update process,
https://wiki.teltonika-networks.com/view/RUT9xx_Bootloader_Upgrade
Teltonika will not provide the files to execute a bootloader update despite requests on this forum and direct requests. So this manual page is incorrect in suggesting that a bootloader update is a potential solution which is not available