BIOS / EFI firmware image for the Apple MacBook Pro Unibody A1286 on logic board 820-2533, revision B, compressed in a RAR archive. A1286 is the 15-inch unibody model number and 820-2533 is the Apple logic board part number. The dump is meant for rewriting the SPI boot ROM with an external programmer when a board will not chime or start because of corrupt firmware. Read and save the original chip first, confirm the chip size matches the image, and expect serial number and machine-specific data to need correcting afterwards.
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 →