If you want to update an existing version of LILO with a newer one, the process is the same as a first-time installation except that existing configuration files are renamed to .old. For example, chain.b is renamed to chain.old. If the new version of LILO behaves properly, you can delete the .old files. Whenever you update the version of LILO, you must update the boot sector to add the new locations and map file format. To update the boot sector, run LILO.