diff --git a/prompt b/prompt
index 6e53c8d..017f634 100644
--- a/prompt
+++ b/prompt
@@ -43,10 +43,10 @@ last_status () {
 }
 
 virtual_env() {
-    local prefix=" %{$fg_bold[green]%}(%{%b$fg[green]%}"
+    local prefix="%{$fg_bold[green]%}(%{%b$fg[green]%}"
     local suffix="%{$reset_color$fg_bold[green]%})%{$reset_color%}"
     [[ -n ${VIRTUAL_ENV} ]] || return
-    printf "${prefix}${VIRTUAL_ENV:t}${suffix}"
+    printf '%s' "${prefix}${VIRTUAL_ENV:t}${suffix}"
 }
 
 prompt_chars() {
@@ -54,7 +54,7 @@ prompt_chars() {
     if $(git rev-parse --is-inside-work-tree >/dev/null 2>&1); then
         local git_char="%{$fg_no_bold[blue]%}±%{$reset_color%}"
     fi
-    printf "%s" "${_GIT_CHAR}$(last_status) $(color_prompt_char)"
+    printf '%s' "${_GIT_CHAR}$(last_status) $(color_prompt_char)"
 }
 
 charge_batterie() {
@@ -102,8 +102,8 @@ prompt_msg () {
         git_network_unreachable)
             msg="Can't reach rc git repo";;
         update_sys*)
-            nb_pkg=$(printf "$line" | grep -o '[0-9]*' | head -n 1)
-            msg="Update ready for the system. $nb_pkg new package$([ $nb_pkg -gt 1 ] && printf "s")";;
+            nb_pkg=$(printf '%s' "$line" | grep -o '[0-9]*' | head -n 1)
+            msg="Update ready for the system. $nb_pkg new package$([ $nb_pkg -gt 1 ] && printf 's')";;
         *)
             msg="";;
     esac
diff --git a/zshrc b/zshrc
index da15b5d..d6e3da2 100644
--- a/zshrc
+++ b/zshrc
@@ -34,6 +34,9 @@ export PKG_CONFIG_PATH="/opt/ros/indigo/lib/pkgconfig:$PKG_CONFIG_PATH"
 RC_PATH=$(dirname "$(readlink -f ${(%):-%x})")
 
 # Import utility functions
+# Colors needed for the prompt definition
+autoload -U colors
+colors
 . "$RC_PATH/functions"
 . "$RC_PATH/aliases"
 . "$RC_PATH/prompt"
@@ -140,7 +143,7 @@ zstyle ':completion:*' cache-path ~/.zs
 ######################
 
 zmodload zsh/complist
-autoload -U compinit promptinit colors
+autoload -U compinit promptinit
 compinit
 colors
 autoload -U zsh-mime-setup