BIOS files for the Dell OptiPlex 7020 desktop, with the name noting both a 4 MB and an 8 MB image, which matches a board carrying two SPI flash chips of those sizes. The ZIP is about 7.2 MB. Each image goes to its own chip, so identify the parts on the board and write the right file to each with a programmer. Read and save the existing contents first, since they hold service tag and ME data, and make sure every image matches its chip capacity exactly.
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 .zip file
Compressed archive that every operating system opens without extra software.
Back up your own chip before writing any dump, and match the full board number and revision. Flashing guide →