Apple Mac BIOS (EFI firmware) for logic board 820-2936, revision B, with 1278 in the name referring to the model number, packed as a 3.78 MB RAR. Apple 820-xxxx numbers are its own logic board part numbers. Technicians write such an image to the boot ROM chip with a programmer to fix a board that will not chime or start. An Apple firmware image also stores machine-specific data such as the serial number, so keep a backup of the original chip contents and transfer them when needed. Confirm the board number first.
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.
All sources (4)
The same file was posted more than once. If one link is dead, try the next.
| Channel | Posted | |
|---|---|---|
| @biosarchive | 11 Apr 2020 | Open file on RM Schematics |
| @laptexlaptopbios | 8 Jul 2020 | Open file on RM Schematics |
| @one5technology | 21 Nov 2020 | Open file on RM Schematics |
| @skclappybios | 10 Apr 2024 | Open file on RM Schematics |
How to open a .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.
Back up your own chip before writing any dump, and match the full board number and revision. Flashing guide →