Firmware dump for an Apple iMac A1418, EMC 2889, with logic board 820-00430-A, packed in a 3.82 MB RAR archive. The A1418 model and EMC number are printed on the case, while the 820 number is on the board. Such an image is written to the SPI boot ROM chip with a programmer when firmware corruption prevents startup. Read the original chip first, since it holds machine-specific serial data, and make sure the file size and board number match before programming.
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 →