[HELP] ESXi 6.5 install hanging - little sanity remaining!

I'm stuck on troubleshooting an esxi 6.5 install. I've had an installation working on this machine before (whitebox) recently, but can't figure out why the install is getting stuck!

It hangs at VMKUSB loaded successfully. I've removed all devices down to mobo ram and cpu, no SAS card, no hard drives, swapped ram, reset and cleared bios. I've booted both with and without UEFI, booted from multiple other USBs. I've taken the usb from a known working host and that hangs at the same point.

The thing that's making me pull my hair out is that I know that this hardware works!! Any ideas or help would be very much appreciated!

Hardware is: Intel DQ67SW with i5-2400, 16gb DDR3 (non-ecc).

Cheers!!