BIOS firmware for an Apple iMac 16,2, model A1418, EMC 2889, on logic board 820-00034-A, archived in a 3.81 MB RAR. Apple identifies logic boards with 820-series numbers, and the A suffix marks the revision. The file serves to reprogram the EFI boot ROM chip with a programmer when the machine has no chime, will not boot or has a corrupted firmware. Read and save the original ROM first since it holds serial and configuration data, and confirm the chip capacity matches.
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 →