Firmware archive for the ASUS K50IJ, where the 218 suffix most likely refers to the BIOS version, though the name does not say so explicitly. The RAR is roughly 590 KB and should hold an image for the board SPI flash chip. Confirm the board model on the PCB, read and keep the existing chip contents with your programmer, and compare the extracted file size with the chip capacity, because an image that does not fit cannot be written correctly.
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 →