install loop for high sierra

Hi, all.

I have a GA-Z77 DS3H with a GTX 980TI that I'm trying to get to high sierra. I've been on Sierra and stable but I thought I'd try a vanilla install. I've stripped it down to a single 6tb Toshiba SATA drive hooked up to one of the fast SATA ports. Bios settings are optimized defaults with achi of the drives and the serial port disabled.

I followed the vanilla instructions (and thank you for the python scripts) and got a USB bootable stick. run through, format the drive to extended-journaled, install OS. Installs for 9 minutes and restarts. Pick my usb drive in bios and the usb install stick is my only option for booting, which just takes me back to the installer. I can repeat this cycle a zillion times. I tried with the unibeast or whatever tonymac has and had the same problem, too.

I know I'm a couple of generations behind in OS, but I'm holding out for NVIDIA drivers or godot, whichever comes first.