There is no longer an installation with the ArchivistaBox, rather the system is booted from CD/USB stick. Normally the associated ISO file is saved directly on the ArchivistaBox (the internal hard disk). To start up a new release, you normally use the online update, see 2.5.
If the online update fails (this is the case, for example, if the ArchivistaBox has no access to the Internet at all), any ArchivistaBox can be booted from CD/USB stick. Instructions on how to manually obtain your personal ISO file are available with separate documentation.