RAR archive of 2.73 MB holding firmware for Apple logic board 820-2936 revision A. The compressed size suggests a single EFI dump packed inside; the exact contents are not listed in the name. Extract it with WinRAR or 7-Zip and write the image to the SPI flash chip using a hardware programmer. Check the board number on the PCB, back up the existing chip contents, and confirm the extracted image size matches the flash capacity before programming.
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 @efibios. 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 →