BIOS for the ASUS Prime B450M-A II desktop motherboard, an AM4 board with the AMD B450 chipset, stored as a 44.9 MB RAR. The name gives no version, so check the archive for the file and its notes. Official ASUS images are commonly flashed through EZ Flash or BIOS FlashBack, while a raw dump is written with an SPI programmer when the board is bricked. Make sure the CPU you use is supported by the version, back up the existing chip and confirm the image fits 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 @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 →