ZIP archive of 3.33 MB for the ASUS X550JX. The number 204 in the name most likely refers to BIOS version 204, though it could also be a board revision such as 2.04. Extract it to see whether it holds an official update capsule or a raw SPI dump. Raw images are written with a programmer, while capsule files need the vendor flash utility. Compare the image size with the flash chip capacity and save the board's original contents before any write operation.
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 .zip file
Compressed archive that every operating system opens without extra software.
Back up your own chip before writing any dump, and match the full board number and revision. Flashing guide →