EFI firmware dump for the Apple MacBook A1181, project M42c, logic board 820-1889-A, compressed as a 1.14 MB ZIP archive. Apple identifies logic boards with 820-xxxx numbers followed by a revision letter, and the dump should match both. Technicians program such an image to the boot ROM chip with an SPI programmer to fix no-boot or no-chime faults caused by corrupted firmware. Read and keep the original chip contents, as they hold machine-specific data like serial number, before writing.
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 (5)
The same file was posted more than once. If one link is dead, try the next.
| Channel | Posted | |
|---|---|---|
| @biosarchive | 4 Jan 2020 | Open file on RM Schematics |
| @laptexlaptopbios | 9 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 |
| @sboisworld | 29 Apr 2025 | Open file on RM Schematics |
How to open a .zip file
Compressed archive that every operating system opens without extra software.
Back up your own chip before writing any dump, and match the full board number and revision. Flashing guide →