diff --git a/bootstrap.sh b/bootstrap.sh
index dd40508..e6a0466 100755
--- a/bootstrap.sh
+++ b/bootstrap.sh
@@ -1,3 +1,4 @@
+#! /usr/bin/env bash
 FILE="$(realpath "${BASH_SOURCE[0]}")"
 ROOT="$(dirname "${FILE}")"
 
@@ -8,7 +9,6 @@ KEY_PATH="${KEY_DIRECTORY}/id_${KEY_ALGORITHM}"
 KEY_PUBLIC='AAAAC3NzaC1lZDI1NTE5AAAAIPHCNcgHlQoiNTXfnUZYvHz9OZwYsmBCrSSV7a7Zche5'
 PACKAGES=(
 'openssh-client'
-'python3'
 'rsync'
 'tree'
 )
@@ -40,6 +40,3 @@ echo "${SERVER} ssh-${KEY_ALGORITHM} ${KEY_PUBLIC}" \
 # packages
 apt-get install --yes "${PACKAGES[@]}" \
 || exit
-
-# remove
-rm --force --recursive "${ROOT}"
diff --git a/cd.sh b/cd.sh
index 3dae9f5..c362a84 100644
--- a/cd.sh
+++ b/cd.sh
@@ -1,33 +1,100 @@
 NAMESERVERS=(
 '9.9.9.9'
 )
-PACKAGES=(
-'ca-certificates'
-'git'
-)
 REPOSITORY='rwx.work/cd'
 
+echo "
+ 1/14 set name servers
+"
 for nameserver in "${NAMESERVERS[@]}" ; do
     echo "nameserver ${nameserver}" \
     >> '/etc/resolv.conf' \
     || exit
 done
 
+echo "
+ 2/14 configure package manager
+"
 echo -n "\
+Acquire::Check-Valid-Until True;
 APT::Get::Show-Versions True;
 APT::Install-Recommends False;
 APT::Install-Suggests False;
+Dir::Etc::SourceParts '';
 " > '/etc/apt/apt.conf.d/apt.conf' \
 || exit
+echo "
+ 3/14 configure package repositories
+"
+echo -n "\
+deb https://deb.debian.org/debian bookworm main
+deb https://deb.debian.org/debian bookworm-backports main
+deb https://deb.debian.org/debian bookworm-updates main
+deb https://deb.debian.org/debian-security bookworm-security main
+" > '/etc/apt/sources.list' \
+|| exit
+
+echo "
+ 4/14 disable package verification
+"
+echo -n "\
+Acquire::https::Verify-Peer False;
+" > '/etc/apt/apt.conf.d/https' \
+|| exit
+echo "
+ 5/14 update package catalog
+"
 apt-get update \
 || exit
-apt-get install --yes "${PACKAGES[@]}" \
+echo "
+ 6/14 install CA certificates package
+"
+apt-get install --yes 'ca-certificates' \
+|| exit
+echo "
+ 7/14 enable package verification
+"
+rm '/etc/apt/apt.conf.d/https' \
+|| exit
+
+echo "
+ 8/14 update package catalog
+"
+apt-get update \
+|| exit
+echo "
+ 9/14 upgrade packages
+"
+apt-get upgrade --yes \
+|| exit
+
+echo "
+10/14 install Git
+"
+apt-get install --yes 'git' \
 || exit
 
 DIRECTORY="$(mktemp --directory)" \
 || exit
+echo "
+11/14 clone Continuous Delivery
+"
 git clone \
 "${GITHUB_SERVER_URL}/${REPOSITORY}" \
 "${DIRECTORY}" \
 || exit
+
+echo "
+12/14 install Python
+"
+apt-get install --yes 'python3' \
+|| exit
+echo "
+13/14 clean package cache
+"
+apt-get clean \
+|| exit
+echo "
+14/14 bootstrap
+"
 "${DIRECTORY}/bootstrap.sh"