Sony firmware archive for the MBX-189 mainboard, labelled with the M760 code, packed as a 780 KB RAR. The name does not say whether it holds the main BIOS or another controller image, so open the archive and compare the file size with the flash chip on the board before programming. MBX is Sony's internal VAIO board numbering, printed on the PCB, and it should match exactly. As with any dump, save a read of the existing chip with your programmer first so you can return to the factory state if needed.
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 @biosbigarchives. 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 →