diff --git a/bootstraps/bootstrap-install b/bootstraps/bootstrap-install
index 029c2f7e40ba1e6bf6f3813c60ddf23703e9db25..78599a64ec5e65bc56fb9e363ed02841f4ab15fc 100644
--- a/bootstraps/bootstrap-install
+++ b/bootstraps/bootstrap-install
@@ -193,14 +193,18 @@ crontab -u seed_mec -r
 if ! test -n "${PROJECTOR}" -o -f "/usr/sbin/projetor" -o \
           -f "/etc/cmpc-release" -o -n "${UCA_SERVER}" -o \
           -n "${UCA_CLASSMATE}"; then
+    # Remove any possible line containing a rule for seed_mec user before adding
+    # root permissions in the sudoers file
+    TMPFILE=$(mktemp)
+    sed '/^seed_mec[\t ]*ALL=(ALL/d' /etc/sudoers > "${TMPFILE}"
+    mv "${TMPFILE}" /etc/sudoers
+    chmod 440 /etc/sudoers
     # Add root permissions to seed_mec user, without the need of password
-    if ! grep -q "seed_mec" /etc/sudoers; then
-        if ! $(echo -e "seed_mec\tALL=(ALL) NOPASSWD: ALL" >> /etc/sudoers)
-        then
-            printf "ERRO: Falha ao adicionar permissões de super-usuário %b" \
-                   "ao usuário seed_mec.\n"
-            exit 3
-        fi
+    if ! $(echo -e "seed_mec\tALL=(ALL) NOPASSWD: ALL" >> /etc/sudoers)
+    then
+        printf "ERRO: Falha ao adicionar permissões de super-usuário %b" \
+           "ao usuário seed_mec.\n"
+        exit 3
     fi
 fi