820-4668 – Apple A1418
The Apple A1418 is built on the 820-4668 board. The catalog lists 2 files for it: 1 BIOS file and 1 schematic.
Revisions seen in file names: A. The earliest file dates from May 2023 (Schematics & Boardviews Archive, Cyberlan Electronics and BIOS Archive).
BIOS dumps 1
Schematics 1
Board facts
| Board number | 820-4668 |
|---|---|
| Numbering | Apple board number |
| Revisions | A |
| First seen | 2023-05-29 |
| Source channels | Schematics & Boardviews Archive, Cyberlan Electronics, BIOS Archive |
| About the number | Apple logic boards are numbered 820-xxxx or 820-xxxxx; the trailing letter is the revision. |
Apple models for this logic board
| A-number | Model | Years |
|---|---|---|
| A1418 | iMac 21.5-inch | 2012–2019 |
A-numbers come from the file names; the model names and years are Apple's published identifiers.
Laptops that use 820-4668
What these files are for
A BIOS dump is a full image of the board's SPI flash chip. It is written back with an SPI programmer when the original firmware is corrupted, after a chip replacement, or to recover from a failed update. Read and save the original chip first: serial number, DMI data and the Intel ME / AMD PSP state differ between boards.
A schematic is the circuit diagram of the main board: power rails, power-up sequence, component values and net names. It is the reference for measuring voltages and tracing a fault.
Tools to open these files
| Format | What it is | Open with |
|---|---|---|
| PDF schematic | any PDF reader; Sumatra PDF and Foxit handle large schematics well | |
| .rar | RAR archive | 7-Zip or WinRAR |
| .bin | BIOS image inside the archive (usually .bin) | a CH341A, XGecu T48 / TL866II Plus or RT809H programmer |
Questions
Is there a boardview for 820-4668?
No boardview has been indexed for 820-4668 yet; the schematic is available on this page.
Which laptops use the 820-4668 board?
Files in the catalog link 820-4668 to the Apple A1418.
Where do the download links go?
Each button opens the original public Telegram post the file was shared in. ChambersDesignInc.com only indexes and cross-references those posts.