BIOS image for a Lenovo G500 in ROM format, 4.5 MB, with no board number or revision noted. The 4.5 MB size suggests a combined dump of a 4 MB main BIOS and a 512 KB second chip, common on these Lenovo boards, so it may need splitting before programming. Check the flash chips fitted to your motherboard and its markings, read and save the original contents first, and write the correct part to each chip with an SPI programmer such as CH341A, then verify the write.
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 .rom file
A BIOS image as shipped by the vendor (commonly AMI) — often the BIOS region only, without descriptor or ME.
Back up your own chip before writing any dump, and match the full board number and revision. Flashing guide →