BIOS archive for an Apple MacBook model A1502 on logic board 820-4924, revision A, packed as a 3.76 MB RAR. Apple numbers its logic boards with the 820-xxxx pattern, which is printed on the PCB and is the key to matching firmware. The BB tag is not explained in the name, so check the files inside. Write the image to the SPI flash with a programmer when the Mac fails to boot or is locked by a firmware problem. Back up the original chip first, and confirm the board number and chip size match.
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 (12)
The same file was posted more than once. If one link is dead, try the next.
| Channel | Posted | |
|---|---|---|
| @biosarchive | 8 Nov 2020 | Open file on RM Schematics |
| @schematicslaptop | 8 Nov 2020 | Open file on RM Schematics |
| @biositechyangiyer | 2 Dec 2020 | Open file on RM Schematics |
| @biositechyangiyer | 1 Feb 2021 | Open file on RM Schematics |
| @pepeelectronica | 24 Apr 2022 | Open file on RM Schematics |
| @biosdumpcomputer | 26 May 2022 | Open file on RM Schematics |
| @biosdumpcomputer | 26 May 2022 | Open file on RM Schematics |
| @boardviewsandachematics | 2 Sept 2025 | Open file on RM Schematics |
| @cyberlanelectonik | 4 Jul 2026 | 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 |
| @schematics_bios | 14 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 →