I suspect I need to repair the bootloader as the Firmware files for these 955 files are official from Teltonika’s RUT955 Firmware repository. But I Cannot find any source files for the 955 bootloaders.
From screenshot I can see you have legacy firmware. So try upload legacy firmware file ( RUT9XX_R_00.06.09.5_WEBUI.bin) and not newest available (RUT9_R_00.07.06.17_WEBUI.bin):
Could you please let me know if downloading version 06.09.5 and then updating to 07.06.17 helped resolve the issue?
Or do you still need assistance with it?