I'm trying to install openSUSE on my new Thinkpad T470p but it fails in two
ways.

1. Both openSUSE-Leap-42.3-DVD-x86_64.iso and openSUSE-Leap-42.3-NET-x86_64.iso
are not bootable from any USB device when UEFI is enabled (secure boot
disabled).
Forcing the BIOS to legacy mode makes them boot.

2. When I install LEAP 42.3 in BIOS legacy mode, the installation works fine
but after a reboot openSUSE is not being booted. The BIOS ignores the disk.
My disk is a NVMe SSD. openSUSE installs grub to the /dev/nvmeXXX device, I've
double checked.

I tried multiple different USB devices with no success.
Fedora 26, on the other hand, boots fine from the USB device, also with secure
boot enabled, and after the installation Fedora is also bootable from the NVMe.

What kind of information can I provide to figure why openSUSE does not boot on
my laptop?