linuxkit/tools/mkimage-raw-efi/README.md

ESP Structure Overview

The script initializes an EFI System Partition using mkfs.vfat and populates it with directories and files for systemd-boot and a Linux Unified Kernel Image (UKI).

Partition Layout

ESP
├── EFI
│   ├── BOOT # contains exactly one of the bootloader binaries below for the respective architecture
│   │   ├── BOOTX64.EFI # amd64
│   │   ├── BOOTAA64.EFI # arm64
│   │   └── BOOTRISCV64.EFI # riscv64
│   └── Linux
│       └── linuxkit.efi # LinuxKit Unified Kernel Image (UKI)
└── loader
    └── loader.conf # systemd-boot configuration file

UKIs in EFI/Linux do not need an explicit entry in loader/entries but are automatically picked up by systemd-boot.