Apple firmware image for a MacBook Air A1466 logic board numbered 820-00165, revision A as written in the name. The raw .bin is 8.00 MB, matching the 64 Mbit SPI flash typically used to hold the EFI boot ROM on such boards. Technicians write it with a programmer such as a CH341A or RT809 when a board fails to chime, stays dark or is locked. Read and save the original chip first, because it holds serial, MAC and other unique system data, and confirm the 820 number printed on the PCB before flashing anything.
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 @bioshub. 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 →