Description of problem:
Install of 64-bit Fedora 27 (LXDE live spin) to its own / and existing /boot/efi made existing Windows 10, Fedora 25, Fedora 26 (as well as new Fedora 27) unbootable.  During the install of Fedora 27, there was an error message about install of boot failed.  Now, when I power on the computer and end up at a boot menu, when I pick Fedora, I get a blank screen for a second or so and back at the boot menu.  When I pick Windows, I also get a blank screen for a second or so and back at boot menu.  I have restored the /boot/efi partition from a backup and the problem still exists.  I am now in the process of restoring the entire disk from a backup (takes 2 hours).

Version-Release number of selected component (if applicable):
Fedora 27 LXDE live spin.

How reproducible:
Have tried once so far.
Will try a second time (this time with BIOS in UEFI only)

Steps to Reproduce:
BIOS:  Both UEFI and CSM compatibility with CSM tried first.
Partitions:  GPT (not MBR); a mixture of OS and data partitions.
Disk:  Solid state disk via nvme (not sda)
System had existing 64-bit versions of Windows 10, Fedora 25, Fedora 26.
Boot Fedora 27 live on USB memory stick.  Do install to hard disk.  Pick / (format) and /boot/efi (existing).
Get error message about boot install failure.  Rest of install finished.

Actual results:
System is unbootable

Expected results:
Should be able to boot Windows 10, Fedora 25, Fedora 26, Fedora 27.

Additional info: