To enable the use of the magic SysRq option type the following at the command prompt:

echo 1 > /proc/sys/kernel/sysrq

Then to reboot the machine simply enter the following:

echo b > /proc/sysrq-trigger

[magic SysRq](https://www.recitalsoftware.com/blogs/17-howto-force-a-immediate-reboot-of-a-remote-linux-machine)