Hey! I’m having trouble installing big sur on an iMac9,1.

I’m using opencore 1.0.1 (not 1.1.0 or whatever the latest is because it WILL NOT create a USB no matter what I do) it gets stuck on less than a minute remaining for at LEAST 4 hours. When I force reset it, it gets stuck on almost no progress on the progress bar. Any help is appreciated, thanks!