Firmware dump for an Apple logic board numbered 820-2530-A, with no model name stated, packed as a 1.28 MB RAR. Apple prints these 820- numbers on the logic board, and the number identifies the exact board family, so check it before use. Such a dump is written to the boot ROM with an SPI programmer to recover a machine with corrupted EFI firmware. Read the existing chip first because it holds serial and configuration data, and confirm the image fits the chip size.
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 →