From Syslinux Wiki

[edit] About

reboot.c32 is a COM32 module for Syslinux that is able to reboot the PC.

It supports cold and warm rebooting.

[edit] Syntax

reboot.c32 [-w] [--warm]

[edit] Example

LABEL cold_reboot
  COM32 reboot.c32

LABEL warm_reboot
  COM32 reboot.c32
  APPEND -w

LABEL warm_reboot2
  COM32 reboot.c32
  APPEND --warm