Firmware package for the SR-T30 PRO receiver in its Jordan1 variant, version V131, dated 17 November 2021, packed as a 5.60 MB RAR. A matching Jordan2 package exists, so confirm which build your receiver ran before choosing this one. Unpack it to find the update image, then load it through the receiver USB update or write it to the flash chip with a programmer. Saving a copy of the existing flash first lets you revert if the box fails to start after flashing.
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.
7-ZipWinRARThe Unarchiver (macOS)