Working EFI firmware for Apple logic board 820-00426 revision A, delivered as an 8.00 MB .bin file. The work label indicates the image was taken from or confirmed on a functioning board. Technicians use it to reprogram the SPI flash chip with a CH341A, RT809H or comparable programmer when firmware corruption prevents startup. Match the 820 number and revision silkscreened on the PCB, read the original chip before erasing, and remember the donor serial number will be embedded unless replaced.
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 →