https://en.opensuse.org/openSUSE:UEFI#The_Boot_Manager
Kolla så du inte måste enabla support för Secure Boot.
How to enable or disable Secure Boot support
"Secure Boot support in openSUSE 12.3 is still considered experimental. The installation program YaST can not automatically detect whether secure boot is enabled. During the installation it offers an option to manually enable Secure Boot support. Turning that option on is required for shim to be installed. To enable or disable support for Secure Boot in an installed system the YaST bootloader module can be used."
Nu kanske det inte behövs i nyaste OpenSUSE men skadar inte att kolla.
Och om du inte redan gjort det, se till att du har uppdaterat till senaste BIOS också.