5.1.2 Kexec with grub2-emu

GRUB can be run in userspace by invoking the grub2-emu tool. It will read all configuration scripts as if booting directly (see Loading an operating system directly). With the --kexec flag, and kexec(8) support from the operating system, the linux command will directly boot the target image. For systems that lack working systemctl(1) support for kexec, passing the --kexec flag twice will fallback to invoking kexec(8) directly; note however that this fallback may be unsafe outside read-only environments, as it does not invoke shutdown machinery.