diff --git a/src/usr/local/www/diag_backup.php b/src/usr/local/www/diag_backup.php
index 0c502dc907..f54ef521bf 100644
--- a/src/usr/local/www/diag_backup.php
+++ b/src/usr/local/www/diag_backup.php
@@ -328,7 +328,8 @@ if ($_POST) {
 
 								if (file_exists("/boot/loader.conf")) {
 									$loaderconf = file_get_contents("/boot/loader.conf");
-									if (strpos($loaderconf, "console=\"comconsole")) {
+									if (strpos($loaderconf, "console=\"comconsole") ||
+									    strpos($loaderconf, "boot_serial=\"YES") {
 										$config['system']['enableserial'] = true;
 										write_config(gettext("Restore serial console enabling in configuration."));
 									}
@@ -336,7 +337,8 @@ if ($_POST) {
 								}
 								if (file_exists("/boot/loader.conf.local")) {
 									$loaderconf = file_get_contents("/boot/loader.conf.local");
-									if (strpos($loaderconf, "console=\"comconsole")) {
+									if (strpos($loaderconf, "console=\"comconsole") ||
+									    strpos($loaderconf, "boot_serial=\"YES") {
 										$config['system']['enableserial'] = true;
 										write_config(gettext("Restore serial console enabling in configuration."));
 									}