The Internet Archive has saved countless old download pages. Try searching for the original MStar FTP directory (now defunct) or a known hosting site from 2012-2015. You may find the original .7z or .zip file untouched.
This is the most risky category. Sites like softdog.com.cn , onlinedown.net , mydown.yesky.com , and huajunxiazai.com host many versions, but they are not official sources. mstar isp utility v475 download link
If you can tell me the or mainboard number you are trying to repair, I can help you find the correct firmware file for that board. Additionally, The Internet Archive has saved countless old download pages