Se actualiza los ponSerialNumbers a minúscula en la DB. En la vista figura en mayúscula.

src/FTTHBundle/Admin/ONUAdmin.php

@@ -41,7 +41,7 @@ class ONUAdmin extends WorkflowBaseAdmin
             ->add('ip')
             ->add('mac')
             ->add('serialNumber')
-            ->add('ponSerialNumber')
+            ->add('ponSerialNumber', 'string', array('template' => 'FTTHBundle:ONU:base_list_field_pon_serial_number.html.twig'))
             ->add('profile')
             ->add('nap')
             ->add('model')

src/FTTHBundle/Entity/ONU.php

@@ -267,7 +267,7 @@ class ONU implements DeviceInterface, TenancyIdTraitInterface, LocationInterface
      */
     public function setPonSerialNumber($ponSerialNumber)
     {
-        $this->ponSerialNumber = $ponSerialNumber;
+        $this->ponSerialNumber = strtolower($ponSerialNumber);
 
         return $this;
     }
@@ -279,7 +279,7 @@ class ONU implements DeviceInterface, TenancyIdTraitInterface, LocationInterface
      */
     public function getPonSerialNumber()
     {
-        return $this->ponSerialNumber;
+        return strtolower($this->ponSerialNumber);
     }
 
     /**

src/FTTHBundle/Resources/views/ONU/base_list_field_pon_serial_number.html.twig

@@ -0,0 +1,7 @@
+{% extends 'SonataAdminBundle:CRUD:base_list_field.html.twig' %}
+
+{% block field %}
+
+    {{ object.getPonSerialNumber()|upper }}
+
+{% endblock %}