BIOS and EC firmware package for the Sony board MBX-266, Z50CR S1202-2 with reference 4RM01, in a 2.47 MB ZIP. Including the embedded controller code matters because a corrupt EC can prevent power-on even with a good BIOS. Sony labels its VAIO mainboards with the MBX- prefix. Write each image to its respective chip with an SPI programmer, backing up the originals first, and make sure the file sizes match the flash parts and the board codes match the PCB.
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 →