Older firmware archive for a W540 laptop, listed as board LKN-1 with Wistron number 12291-2 and tagged OLD, 2.76 MB in RAR form. The name differs from the LKM-1 variant used elsewhere, so check the code printed on your board. The tag suggests an earlier BIOS release, useful for restoring a board or rolling back after a problem update. Extract the contents, check the image size against the target flash chip, and back up the existing chip before programming it with an SPI programmer.
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 @SCHEMATICWORLD. 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.