ASUS UX305UA BIOS file in a 3.51 MB RAR archive; the name gives only the model, with no version or revision. Expect a full SPI flash image for recovering this ZenBook when the firmware is corrupted. Flash it with an external programmer such as a CH341A or an RT809 series unit, after saving the original chip contents so model-specific data is not lost. Compare the image size with the capacity of the chip on the board before programming.
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 →