David Heinemeier Hansson wrote that the menu lists the installed kernels and marks the one Limine boots by default, and that it uses the wide layout Fonts uses so a long kernel name fits. He wrote that a 30-second notification says "Now using <kernel>" and "Reboot to use new default kernel", and that clicking it reboots.

Hansson wrote that picking a kernel switches the default with a single pkexec prompt. He wrote that omarchy-kernel set refuses a kernel that is not installed, and that it refuses when Direct Boot is active, because the firmware skips Limine then.

Hansson wrote that, as root, the command writes the chosen kernel first in the boot order, rebuilds only that kernel, and checks that the kernel is the first entry. He wrote that if the rebuild or the check fails, it restores the previous boot order and rebuilds the previous default.

Hansson wrote that he ran omarchy-kernel set linux-omarchy on an x86 Limine machine through the pkexec path. He wrote that it took one prompt, rebuilt only that kernel, passed the --tree check, and left the boot order correct.