Main BIOS file for the Lenovo IdeaPad S400, sold as a 3.74 MB RAR archive. The name gives no motherboard number or revision, so you will need to identify the board from its PCB markings and confirm compatibility yourself. Main typically refers to the primary system BIOS image rather than EC firmware. Such dumps are flashed with an SPI programmer to revive dead or boot-looping boards. Read and save the original chip contents first, and check that the extracted binary size equals the flash capacity.
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 @afsbiosfree. 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 →