Firmware archive for the HD BOX 500S receiver, version V1.19B2 built on 20130509, size 2.85 MB. It is an older platform than the S500 releases from 2017, so do not mix the two despite the similar model names. Technicians apply such images to recover a dead or looping receiver, usually through RS232 with the manufacturer's loader. Verify the model plate and main board before writing anything. Dump the existing flash first so the original software can be restored if the new image does not fit.
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.