BIOS archive for the MA18 mainboard 15315-1M, with the board's full part number 448.09U02.001M also given. The 15315 code and the 448 prefix follow the Wistron numbering system, so Wistron is the board manufacturer. The 8.40 MB RAR provides an image for rewriting the SPI flash when the board is bricked or shows no image. Match both numbers against the PCB label, back up the current chip with your programmer before writing, and make sure the image size fits the installed flash part.
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 →