I have not been able to get a supposed bootable QNX 7 USB to actually boot on various x86 64 bit machines. I've tried 
the generic image from the BSP download, and others that I've built from the IDE.
On some machines it just boots into the BIOS settings. On one it hangs with a blank screen (not even a cursor). Most are
 Gigabyte motherboards. For example, Z390 UD, GA-H170M-D3H, GA-H270-Gaming 3.
It does not appear to get to the startup script.
I've tried variation in BIOS settings on the machines. The main one being support for legacy USB. With that enabled, I 
can often see the USB in the boot override selection, but it does not boot.
In most cases I have minimal hardware plugged in.
I can successfully boot using a USB loaded with a QNX 6.6 image.
Any ideas?