BIOS (EFI firmware) dump for the Apple MacBook 15 A1286 on logic board 820-2533 revision A, in a 1.34 MB RAR. Apple boards store the firmware on an SPI flash chip that can be reprogrammed with an external programmer when the Mac will not boot or is locked. Read and back up the original chip first, because it holds unique serial data. Confirm the 820-2533 marking and verify that the image size matches the chip capacity before writing.
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 →