Firmware archive of 1.37 MB for the Sony VAIO VPCCA3S7C on motherboard MBX-239, with a cn1 suffix that may refer to a regional or board marking, though the name does not explain it. MBX numbers are Sony own board designations for VAIO models. A dump like this goes onto the BIOS flash chip via a programmer to recover a laptop that powers on without image or fails to post. Check MBX-239 printed on the PCB, read and store the original chip contents, and confirm the dump size fits the chip.
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 →