diff --git a/install.sh b/install.sh
index 8411e51..4ac6339 100755
--- a/install.sh
+++ b/install.sh
@@ -24,6 +24,8 @@ function assert_supported_distro {
 
 set -Eeuo pipefail
 
+message="${1:-installed}"
+
 [[ "$UID" -ne 0 ]] && echo 'root privilege required' && exit 1
 ! assert_supported_distro && echo 'unsupported distro: debian-like OR arch-like expected' && exit 2
 
@@ -33,5 +35,5 @@ if [[ -d "$MIAOU_BASH_DIR" && -L /etc/inputrc && "$(readlink /etc/inputrc)" == "
 else
   bootstrap
   . "$MIAOU_BASH_DIR"/bin/miaou-bash "$MIAOU_BASH_DIR/lib/init.bash"
-  echo "miaou-bash successfully installed"
+  echo "miaou-bash successfully $message"
 fi
diff --git a/lib/self-upgrade.bash b/lib/self-upgrade.bash
index e184c15..6d4b2ce 100755
--- a/lib/self-upgrade.bash
+++ b/lib/self-upgrade.bash
@@ -1,29 +1,16 @@
 #!/usr/bin/env miaou-bash
 
 # CONSTANTS
+#
 [[ ! -v MAIN_TAR_GZ_URL ]] &&
   readonly MAIN_TAR_GZ_URL="https://git.artcode.re/miaou/miaou-bash/archive/main.tar.gz"
 
 # FUNCTIONS
 
-function bootstrap {
-  cd "$(mktemp -d)" || exit 3
-  curl -s -O "$MAIN_TAR_GZ_URL"
-  tar -xzf main.tar.gz --directory "$(dirname "$MIAOU_BASH_DIR")"
-
-  local source_bin="$MIAOU_BASH_DIR/bin/miaou-bash"
-  local dest_bin="/usr/bin/miaou-bash"
-  if ! cmp -s "$source_bin" "$dest_bin"; then
-    cp -f "$source_bin" "$dest_bin"
-  fi
-  echo "miaou-bash refreshed from: $MIAOU_BASH_DIR"
-}
-
 function self_upgrade {
   mv "$MIAOU_BASH_DIR" "$MIAOU_BASH_DIR".before_upgrade
-  "$MIAOU_BASH_DIR".before_upgrade/install.sh
+  "$MIAOU_BASH_DIR".before_upgrade/install.sh "upgraded"
   rm -rf "$MIAOU_BASH_DIR".before_upgrade
-  echo "miaou-bash successfully updated"
   . "$MIAOU_BASH_DIR"/bin/miaou-bash --version
 }