Firmware dump for an Apple MacBook model A1466 built on logic board 820-3209-A, marked in the name as a fully working BIOS. Packed as a 6.21 MB RAR archive, it is meant for reprogramming the EFI SPI flash on that board when the machine fails to boot or shows a firmware lock. Apple 820-xxxx numbers identify the logic board itself, so check the number printed near the board edge. Always dump and keep the original chip contents first, since serial and model data stored in the image may need transferring to the new file.
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 →