Firmware dump for the Apple logic board 820-4668-A, packed as a 7.11 MB RAR archive and labelled as a fully working BIOS image. Technicians use such a dump to recover a board with a corrupted or locked boot ROM by writing it to the SPI flash with an external programmer. Before flashing, read and save the original chip contents, confirm the board number and revision printed on the PCB match exactly, and check that the image size equals the capacity of the flash chip fitted to the board.
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 (3)
The same file was posted more than once. If one link is dead, try the next.
| Channel | Posted | |
|---|---|---|
| @biosarchive | 29 May 2023 | Open file on RM Schematics |
| @Laptopbiossolutions | 19 Sept 2023 | Open file on RM Schematics |
| @generalbios | 4 Nov 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 →