Dell 7250 BIOS described as an older working file for an 8 MB flash chip. The name gives no board number, so confirm the motherboard and its revision directly before use. The 8 MB note means the image is intended for a 64 Mbit SPI chip, and a dump of a different size will not fit a mismatched chip. Unpack the RAR and check the contents. Before programming with a hardware flasher, read and save the original chip, since Dell firmware carries service tag and system data.
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 →