Firmware dump for an Apple MacBook logic board 820-00426-A, the version with a Core i7 processor, compressed into a 4.46 MB RAR. Apple numbers its logic boards with the 820- prefix, and the suffix letter marks the revision. A clean EFI image is used to replace a corrupted or locked BIOS chip read with a programmer. Make sure the 820 number on your board matches exactly, back up the existing chip before writing, since it holds serial and machine-specific data, and check the dump size against the flash.
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 →