BIOS firmware package for the ASUS E502S and E402SA notebooks, revision 2.1 mainboard, supplied as a RAR archive of 3.80 MB. The name lists both models together, which suggests the two share a board design, but confirm the revision printed on your PCB reads 2.1 before writing anything. Extract the image, read and save the original SPI flash contents with a programmer such as a CH341A, and check that the image size matches the capacity of the chip on the board 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 @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 →