Firmware image for an Apple logic board numbered 820-2223-A, stored in a 2.41 MB RAR archive and labelled as a fully working BIOS. Apple uses the 820 prefix for its logic board part numbers, with the letter suffix showing the revision. Such a dump is normally written to the board's SPI flash with an external programmer when the original firmware is corrupted or locked. Read and keep the existing chip contents before writing, since they may hold machine-specific data such as serial information, and verify the board number engraved on the PCB.
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 | 8 Feb 2024 | Open file on RM Schematics |
| @generalbios | 11 Feb 2024 | Open file on RM Schematics |
| @generalbios | 6 Mar 2024 | Open file on RM Schematics |
| @generalbios | 14 Jul 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 →