A BIOS / firmware dump for Apple hardware (board 820-00426). Shared as “Macbook A1398 2015 820-00426A 8MB TESTED OK .zip” — a .zip file, 4.92 MB.
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 @Laptopbiossolutions. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.
Built-in OS tools7-Zip
Back up your own chip before writing any dump, and match the full board number and revision. Flashing guide →