BIOS (EFI firmware) dump for the Apple A1466 MacBook Air with the i5-4250U processor, logic board 820-3437 revision B, archived as a 3.98 MB RAR. Technicians flash such images to the SPI ROM when a board shows no boot, firmware lock or corruption after a failed update. Use an external programmer with a clip or by removing the chip, and save the existing ROM first since it holds serial and configuration data. Confirm the 820-3437-B marking and CPU variant, and verify the image size matches the flash chip 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 →