Method of installing software on a host computer system and corresponding host computer system

A method of installing main operating software on a host computer system to be operated, wherein the host computer system is initially in a restricted operating state of restricted functionality, the method comprising:

• setting up a connection from the host computer system to a repository server to fetch the main operating software provided in the repository server by the host computer system, wherein the host computer system keeps predetermined network ports used for the method closed such that no external connection establishment to the host computer system is permitted and access to the host computer system via the network by the network ports is therefore prevented,
• fetching the main operating software provided in the repository server by the host computer system,
• automatically installing the main operating software in the host computer system, and
• adopting a main operating state by the host computer system after the main operating software has been successfully installed, wherein the host computer system in the main operating state provides a main functionality going beyond a restricted functionality of the restricted operating state and is controlled by the main operating software.