ASUS X509FJ BIOS dump associated with the Macronix MX25L12805D flash chip named in the file, supplied as a ZIP of 5.53 MB. That part is a 128 Mbit, 16 MB SPI flash, which tells you the expected image size. Use a programmer such as a CH341A with a clip or by removing the chip to reflash it when the laptop fails to boot. Check the chip on your board and the motherboard revision, and read out the existing contents first as a backup.
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 →