diff --git a/docs/public/debian/system/system.rst b/docs/public/debian/system/system.rst
index fc32f61..8bc20cd 100644
--- a/docs/public/debian/system/system.rst
+++ b/docs/public/debian/system/system.rst
@@ -25,18 +25,18 @@ critical base packages
 decide the desired type of system
 ---------------------------------
 
- * will the system run
-   * 64 bits?
-   * 32 bits?
-   * both?
- * will the system be run by
-   * a physical machine?
-   * a virtual machine?
-   * a container?
-   * a container inside a virtual machine?
- * will the system be stored
-   * read-write, as a file system on a dedicated partition?
-   * read-only, as a single file loaded in RAM at boot time?
+* will the system run
+  * 64 bits?
+  * 32 bits?
+  * both?
+* will the system be run by
+  * a physical machine?
+  * a virtual machine?
+  * a container?
+  * a container inside a virtual machine?
+* will the system be stored
+  * read-write, as a file system on a dedicated partition?
+  * read-only, as a single file loaded in RAM at boot time?
 
 Install required tools
 ======================
@@ -57,7 +57,7 @@ prepare the system's directory
 ------------------------------
 
 * become root
-* make a directory and step into it
+* make root directory
 
 .. code:: shell
 
@@ -65,8 +65,7 @@ prepare the system's directory
 
 .. code:: shell
 
- mkdir -p "path"
- cd "path"
+ mkdir '/squashfs-root'
 
 generate the minimal base
 -------------------------
@@ -74,16 +73,55 @@ generate the minimal base
 .. code:: shell
 
  debootstrap \
- --arch="amd64" \
- --include="locales,apt-utils,dialog" \
- --variant="minbase" \
- "stretch" \
- . \
- "miroir"
+ --arch 'amd64' \
+ --variant 'minbase' \
+ --include 'locales,apt-utils,dialog' \
+ 'bullseye' \
+ '/squashfs-root' \
+ 'https://deb.debian.org/debian'
 
 Configure preinstalled packages
 ===============================
 
+define default locale
+---------------------
+
+* etc/default/locale
+
+::
+
+ LANG='en_US.UTF-8'
+ LANGUAGE='en_US:en'
+ LC_CTYPE='fr_FR.UTF-8'
+ LC_NUMERIC='fr_FR.UTF-8'
+ LC_TIME='fr_FR.UTF-8'
+ LC_COLLATE='fr_FR.UTF-8'
+ LC_MONETARY='fr_FR.UTF-8'
+ LC_MESSAGES='en_US.UTF-8'
+ LC_PAPER='fr_FR.UTF-8'
+ LC_NAME='fr_FR.UTF-8'
+ LC_ADDRESS='fr_FR.UTF-8'
+ LC_TELEPHONE='fr_FR.UTF-8'
+ LC_MEASUREMENT='fr_FR.UTF-8'
+ LC_IDENTIFICATION='fr_FR.UTF-8'
+
+define locales to generate
+--------------------------
+
+* etc/locale.gen
+
+::
+
+ en_US.UTF-8 UTF-8
+ fr_FR.UTF-8 UTF-8
+
+generate locales
+----------------
+
+.. code:: shell
+
+ locale-gen
+
 define default keyboard layouts
 -------------------------------
 
@@ -97,35 +135,6 @@ define default keyboard layouts
  XKBOPTIONS=""
  BACKSPACE="guess"
 
-define default locales to generate
-----------------------------------
-
-* etc/default/locale
-
-::
-
- LANG=en_US.UTF-8
- LANGUAGE=en_US:en
- LC_CTYPE="fr_FR.UTF-8"
- LC_NUMERIC="fr_FR.UTF-8"
- LC_TIME="fr_FR.UTF-8"
- LC_COLLATE="fr_FR.UTF-8"
- LC_MONETARY="fr_FR.UTF-8"
- LC_MESSAGES="en_US.UTF-8"
- LC_PAPER="fr_FR.UTF-8"
- LC_NAME="fr_FR.UTF-8"
- LC_ADDRESS="fr_FR.UTF-8"
- LC_TELEPHONE="fr_FR.UTF-8"
- LC_MEASUREMENT="fr_FR.UTF-8"
- LC_IDENTIFICATION="fr_FR.UTF-8"
-
-* etc/locale.gen
-
-::
-
- en_US.UTF-8 UTF-8
- fr_FR.UTF-8 UTF-8
-
 [configure command shell](../bash/index.md)
 -------------------------------------------
 
@@ -158,19 +167,13 @@ switch into context
 
 .. code:: shell
 
- mount --bind /proc proc
- mount --bind /sys sys
- chroot .
+ for f in 'dev' 'dev/pts' 'proc' 'sys' ; do
+     mount --bind "/${f}" "/squashfs-root/${f}"
+ done
+ chroot '/squashfs-root'
 
 .. todo:: /dev
 
-generate locales
-----------------
-
-.. code:: shell
-
- locale-gen
-
 define root password
 --------------------
 
@@ -225,8 +228,8 @@ systemd-sysv      sans quoi le système ne démarrera pas complètement
 
 .. code:: shell
 
- apt-get install -t stretch-backports "linux-image-amd64"
- apt-get install "live-boot"
+ apt-get install -t stretch-backports 'linux-image-amd64'
+ apt-get install 'live-boot'
 
 ----
 
@@ -265,12 +268,13 @@ install useful packages
  less nano vim \
  pciutils usbutils \
  python3 \
- squashfs-tools \
+ squashfs-tools
 
 .. code:: shell
 
- apt-get install -t "stretch-backports" \
- debootstrap \
+ apt-get install \
+ --target-release 'bullseye-backports' \
+ debootstrap
 
 install other packages
 ----------------------
@@ -285,24 +289,25 @@ install other packages
 properly switch back from context
 ---------------------------------
 
-* vider le cache d’APT
+* empty APT's cache
 
 .. code:: shell
 
  apt-get clean
 
-* s’extraire de l’environnement
+* exit the environment
 
 .. code:: shell
 
  exit
 
-* démonter les liens au système hôte
+* untie links to host system
 
 .. code:: shell
 
- umount sys
- umount proc
+ for f in 'sys' 'proc' 'dev/pts' 'dev' ; do
+     umount --lazy "/squashfs-root/${f}"
+ done
 
 clean up commands history
 -------------------------
@@ -319,4 +324,9 @@ Archive prepared file system
 
 .. code:: shell
 
-  mksquashfs . "../name.squashfs" -comp "xz"
+ mksquashfs \
+ '/squashfs-root' \
+ 'filesystem.squashfs' \
+ -b '1m' \
+ -comp 'zstd' \
+ -Xcompression-level 22