On Wed, 26 Apr 2017, Kent West wrote:
> Two identical newish Dell desktops. Configured for non-legacy, UEFI-only
> booting. No Secure-Boot or Fast Boot.
[...]
> Every other boot results in a hang at "Initializing Ramdisk"
This usually is indicative of a video driver (or some other driver)
issue.
Try booting without the quiet option, and possibly with nomodeset, and
see if it works. [You'll have to edit the grub command line to do this.]
Your newish hardware may require a backported kernel to function reliably.