Working BIOS dump for an Apple iMac A1224, read from an MX25L3205 flash chip, a 32 Mbit (4 MB) Macronix SPI part, with a 2023-06-19 date in the name. The image is reported as fully working. Use it to reprogram the boot ROM on a logic board that fails to chime or start, using a programmer that supports this chip. Apple firmware stores machine-specific data such as the serial number, so back up the original chip first and transfer that data if needed. Confirm the image is exactly 4 MB before writing it.
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.
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 →