If this file was downloaded from an unverified forum or "BIOS crack" site, and it lacks a clear header or contains garbled text, it could be a vector for a rootkit or simply a corrupted file that will "brick" the motherboard if flashed.
file biosdsi9.rom stat biosdsi9.rom sha256sum biosdsi9.rom strings biosdsi9.rom | head -n 200 binwalk -e biosdsi9.rom uefitool -l biosdsi9.rom strings -a biosdsi9.rom | egrep -i 'pass(word)?|private|ssh-rsa|BEGIN RSA PRIVATE KEY|DEBUG|JTAG|UART' biosdsi9.rom