NixOS stable & unstable won't boot from usb on XPS 9570

so I just got a Dell XPS 9570, disabled Secure Boot, tried to boot from USB both stable (18.09.2062.f944ffecb98-x86_64-linux) & unstable (19.03pre167858.f2a1a4e93be-x86_64-linux), graphical and minimal, but I always get the same unexpected behaviour: a white, non-blinking underscore in the top-left corner of the screen.
I tried several USB sticks, ISO burned from macOS via sudo dd if=nixos-minimal-19.03pre167858.f2a1a4e93be-x86_64-linux.iso of=/dev/rdisk2 bs=4m.
I’ve also tried booting an ArchLinux ISO from December 2018 and it works fine.
Any ideas?

I experienced this just over the weekend, turns out you need to turn on Legacy Boot in the BIOS for USB now, even though it still seems to end up booting to UEFI.


Thanks, that was indeed the issue.