Firmware archive named only pm800 pro, with no brand, board number or revision given, so its target must be confirmed from the contents. The name may refer to a PM800 chipset or a product model, but that cannot be assumed. The 3.12 MB RAR likely holds a flash image for restoring the board firmware with a programmer. Before using it, compare the chip and board markings, save a backup of the original firmware, and make sure the image size matches the flash chip capacity.
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 @afsbiosfree. 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.
Back up your own chip before writing any dump, and match the full board number and revision. Flashing guide →