StarTrack SRT-550 HD Platinum firmware dated 20180912, without a version number in the name, packed as a 2.75 MB RAR. By date it is newer than the V3758 and V4101 releases from 2017. Check the actual build number inside the archive before use. It suits updating or reviving receivers that freeze or reboot, using USB upgrade or a serial loader. Confirm that the receiver model and hardware match, and save a backup of the current firmware so any problems after flashing can be reversed.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @tvsoftwareworld. Enginerys does not host this file.
How to open a .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.