The Image Management Service now offers the UEFI start mode (Unified Extensible Firmware Interface) for private images in the user interface. UEFI is a specification for a software program that connects a computer's firmware to its operating system. Like the BIOS, UEFI is installed at the time of manufacture and is the first program to run when a computer is turned on.
A list of operating systems that support a specific start mode is automatically displayed on the user interface when the mode is selected. Customers can now select private images in UEFI format directly on the user interface as soon as they create a new image.
For details see https://docs.otc.t-systems.com/image-management-service/index.html