@Ploddles - so during my time trying to tweak RTC settings, I ran into almost all the standard, default, issues, even when trying to boot off of a working EFI (USB). What the root cause of the issue was for me, was the BIOS settings (which gets reset when I have to clear CMOS due to hard shutdowns). And this was after having a working Installation.
Here's a few things to try:
- Clear your CMOS (if you have the button option on your mobo, save your BIOS settings on a USB, or as profile, unplug from wall, clear it with the button, then load it or manually check them again)
- CSM Disabled/4G Encoding Enabled (4G Encoding was disabled which caused my PCI error)
- Clear/Reset NVRAM - reboot, before attempting reinstall. Some cache of it may be left behind from previous installs? I can't verify this.
- If you haven't already, do a full disk erase before installing
See if those things all done prior to the install can help you clear more of the installer. Also for the sake of ruling out other potential issues, make sure you don't have any disks/drives/nvme attached to your mobo that aren't MacOS (Windows, etc) plugged in. Ideally just a single drive that you intend on installing first, and then afterwards, you can add them back in.
@iGPU - I'm noticing a few interesting compatibility quirks that weren't present in the Proxmox Version. A few more apps that I had used fine on BS are now crashing on Catalina. My guess is that it's due to exposing the CPU as AMD vs masking as Intel, and those application drivers aren't loading, as there's no native MacOS AMD drivers. What's your take on this? Another thought around the reset/shutdown issue would be something to do with the USB Power.
Adding some additional useful things below