$ sudo apt-get update
$ sudo apt-get install grml-rescueboot 

grml-rescueboot is installed in your system.

Make ensure the grml-rescueboot package were installed using the commands given below,

$ sudo dpkg-query -l | grep grml-rescueboot *

You will get with grml-rescueboot package name, version, architecture and description in a table

grml-rescueboot package basic information: