Apple logic board firmware dump for board 820-00138, an 8 MB raw binary marked as tested and working. The 820-xxxxx format is Apple's own logic board numbering, so match it with the number on the PCB. Such a file is written to the SPI flash with a programmer to recover a board that fails to boot or is locked by corrupted firmware. Keep a backup of the original chip since it holds serial and configuration data, and confirm the chip is 8 MB 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 @ITHINKHS. Enginerys does not host this file.
Back up your own chip before writing any dump, and match the full board number and revision. Flashing guide →