Gigabyte P55K firmware, marked v5 in the name, probably the board revision, archived as RAR at about 7.9 MB. Check the revision printed on the PCB, as Gigabyte BIOS files are often revision-specific. Many Gigabyte boards of this era use DualBIOS with two flash chips, so identify which chip to program. Read and save the existing contents with an SPI programmer before flashing, and verify that the extracted image size matches the 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 @biosarchive. 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 →