so Im trying a nixOS install on a 2012 imac. I burned to a usb then plugged it in and booted into the usb. I get to the boot screen and select installation media. then it shows some stuff in the terminal then proceeds to turn black, then green, then white, and might swap back to green after a bit but I dont remember. the point is, if I try to boot into the installer usb it goes to a blank screen, any ideas how to fix this?