Working BIOS for the ASUS X421EAYB mainboard revision 2.0, reported as fully tested. Packed in a 9.80 MB RAR, the image is intended for reprogramming the SPI flash when a laptop stays black, restarts in a loop or lost its firmware after a failed update. Use a hardware programmer and always dump the original chip before writing so serial data and settings can be recovered. Check that the board name and revision on the PCB match, and that the file size equals the chip 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 @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 →