MacBook Pro firmware for an A1278 with logic board 820-2936-A and the HM65 chipset per the name, packaged as a RAR. K90I is the internal Apple project code shown in the name. Use it to restore a corrupted boot ROM with an SPI programmer on a board that no longer powers up properly. Revision A may differ from the B boards listed elsewhere, so check the letter on your board. Save the original ROM first, because it holds serial and configuration data.
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 →