Firmware image for an Apple logic board 820-00923, revision A, with the Management Engine region cleared. A cleaned ME region lets the dump be written to a different board without carrying over the donor machine's ME state. Technicians use such images to recover boards with corrupted or locked EFI flash by reprogramming the SPI chip directly. The 820-xxxxx code is Apple's own board numbering, so match it to the number on the PCB, and read and keep a backup of the existing chip before writing this one.</p>
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 →