Firmware for the Openbox HD2 receiver in the 8M variant, version 1.09.9732 dated 20 August 2013, packed as RAR. The 8M tag likely refers to the flash memory size of that hardware version, so it should not be used on units with other memory. Load it through the receiver update procedure or write it to the flash chip with a programmer if the box no longer boots. Check the hardware version on the board and back up the existing firmware before replacing it.
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)