Tested BIOS for the Dell OptiPlex 5050 Tower desktop on motherboard 15127-1, a Wistron-style board number, provided as a 7.42 MB RAR. Desktop boards like this usually carry a socketed or soldered SPI chip that can be read and written with a CH341A or similar programmer when the system will not boot after a failed update. Confirm the board number printed on the PCB matches, read and save the existing chip contents, which contain the service tag, and make sure the image size agrees with the chip capacity before flashing.
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 @generalbios. 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 →