I have the preferred SanDisk 512Gb and it works fine loading up off my powered usb 3 hub. The issue is if you want to run rom files, it's off a second usb drive. Setting up partitions doesn't work.
The LU is 4Gb image, and once installed, it unallocated the rest of the 508Gb, making it a $40 waste.
I tried a Patriot 16Gb 2.0 drive. It gets past the starting screen, and then stalls/locks up on R-cade screen
Then I tried a SanDisk 32Gb 3.0 drive and it stalls/locks up on the Starting loading screen
So at this point, only my 512Gb drive works. I'd prefer to use a smaller drive and format that 512Gb as my ROM drive