Dell OptiPlex 3020 small form factor BIOS for the DIH81R motherboard, board number 12125-1M, packed as a 4.50 MB rar. The 12125-1M style number follows the Wistron pattern, Wistron being the ODM for this board. The H81 in the code points to the Intel H81 chipset. Flash this image to the SPI chip with a programmer when the system shows no POST or corrupted firmware. Back up the original contents, which hold the service tag, and check the image fits the chip capacity 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.
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 →