Firmware binary for the Apple A1989 MacBook Pro on logic board 820-00850-A, zipped to 2.03 MB. A BIN image like this is written to the board's SPI flash with an external programmer when the firmware is corrupted or the chip is replaced. On T2-based Macs firmware handling differs from older EFI machines, so make sure the image suits this board and chip. Read and keep the original contents before writing, and check the dump size matches the flash capacity, since a mismatched image will not fit.
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 .zip file
Compressed archive that every operating system opens without extra software.
Back up your own chip before writing any dump, and match the full board number and revision. Flashing guide →