Firmware dump for Apple logic board 820-01700-A, labelled as the original BIOS, in a 2.29 MB RAR; the (2) suggests a duplicate copy. Apple firmware chips store EFI data and machine-specific information, so a dump from another unit may carry its serial and settings. Technicians write such images with an SPI programmer when the original is corrupt. Read and keep your existing chip contents first, and check that the extracted image size matches your flash chip, because a size mismatch will not program correctly.
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 @schematiclaptopramkushwaha. 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 →