Boot ROM image for the Apple logic board 820-2936, with the b suffix in the name probably indicating board revision B. The 8.00 MB raw binary fits a 64 Mbit SPI flash device. It is written with an external programmer when a Mac board fails to start because its firmware is corrupt. Confirm the full 820 number and revision silkscreened on the PCB before use. Keep a backup of the existing chip, since serial and configuration data in Apple dumps is machine-specific and may need transferring.
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 @bios_laptop. 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 →