+First of all create the chroot using debootstrap (requires root):
+
+ BASECHROOT='/tmp/basefile' # path where the chroot gets generated
+ SUITE='bookworm' # using the current stable release should always work
+ debootstrap --exclude=info,tasksel,tasksel-data,isc-dhcp-client,isc-dhcp-common "${SUITE}" "${BASECHROOT}" http://deb.debian.org/debian
+ tar -C "$BASECHROOT" --exclude='var/cache/apt/archives/*.deb' --exclude 'var/lib/apt/lists/*_*' --xattrs --xattrs-include='*.*' --acls -zcf "${SUITE}".tar.gz ./
+
+[TIP]
+By default debootstrap builds a chroot matching the architecture of the running
+host system. If you're using an amd64 system and want to build an i386 base.tgz
+then invoke debootstrap using the '--arch i386' option. Disclaimer: building an
+AMD64 base.tgz won't work if you are using a 32bit kernel system of course.
+Also building an ARM64 base.tgz requires an arm64 system.
+
+Finally place the generated tarball in /etc/grml/fai/config/basefiles/ (note
+that it needs to be uppercase letters matching the class names, so: e.g.
+AMD64.tar.gz for amd64, I386.tar.gz for i386 or ARM64.tar.gz for arm64).
+
+Then executing grml-live should use this file as base system instead of executing
+debootstrap. Check out the output for something like:
+
+ [...]
+ ftar: extracting //etc/grml/fai/config/basefiles///AMD64.tar.gz to /srv/grml64_testing/grml_chroot//
+ [...]
+
+[[localrepos]]
+How to use your own local repository
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Let's assume you have Debian package(s) in your filesystem inside
+`/home/foobar/local-packages` and want to provide them to your grml-live build.
+This can be achieved either 1) through a bind mount (using the MIRROR_DIRECTORY
+configuration) or 2) by serving a repository via HTTP.
+
+Serving via bind mount / MIRROR_DIRECTORY
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Make sure to create an according sources.list configuration file, e.g. using
+your own class name `CUSTOM`: