Comment 7 for bug 364889

Why not just change /etc/default/kexec to have LOAD_KEXEC=false ?

I had this same problem upon upgrading to 9.04 from 8.10. I do not know if kexec-tools was originally installed; but I do know that the behavior happened immediately after the upgrade. I dual-boot Linux with another OS via GRUB; and this default behavior of kexec-tools made it impossible to reboot to GRUB except by shutdown and re power-on.