An 8 MB BIN firmware image for the Apple logic board 820-3209, described in the name as a Catalina build with the Management Engine region cleaned. A clean ME image helps restore a Mac that fails to boot after flash corruption. Write it to the SPI chip with a programmer, but first dump and keep the original, which carries the serial number and other machine data you may need to transplant. The 8 MB size must match the flash part on the board, and the 820 number on the PCB must agree with this file.
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 @efibios. Enginerys does not host this file.
How to open a .bin file
A raw, byte-for-byte image of a flash chip: the main BIOS / UEFI, the embedded-controller (EC) firmware, or both.
Back up your own chip before writing any dump, and match the full board number and revision. Flashing guide →