Firmware archive for the 13-inch MacBook Pro A1708, EMC 3154 (written ECM3154 in the name), on logic board 820-00840-A, supplied as a 4.55 MB RAR. Newer Apple boards use the longer 820-xxxxx numbering, with the trailing letter showing the revision. Such a dump is written to the SPI ROM with a programmer when the board fails to boot because of firmware corruption. Read and save the original contents first, since they contain machine-specific data, and verify the chip size and PCB board number match.
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 →