EFI firmware for Apple A1418 logic board 820-3588-A, with the flash chip identified as a Macronix 25L6406E, a 64 Mbit (8 MB) SPI part. A1418 is the 21.5-inch iMac model number, and 820-3588 is the board ID printed on the PCB. The 7.41 MB RAR should hold an image for that chip, written with an SPI programmer when the machine will not boot or gets stuck after a failed update. Check the image size matches the chip capacity, and dump the original first so you keep its serial number and system data.
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 (8)
The same file was posted more than once. If one link is dead, try the next.
| Channel | Posted | |
|---|---|---|
| @biosarchive | 14 Jun 2020 | Open file on RM Schematics |
| @laptexlaptopbios | 28 Jun 2020 | Open file on RM Schematics |
| @laptexlaptopbios | 6 Jul 2020 | Open file on RM Schematics |
| @one5technology | 21 Nov 2020 | Open file on RM Schematics |
| @pepeelectronica | 24 Apr 2022 | Open file on RM Schematics |
| @skclappybios | 10 Apr 2024 | Open file on RM Schematics |
| @schematics_bios | 24 Jul 2026 | Open file on RM Schematics |
| @schematics_bios | 1 Aug 2026 | 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 →