diff --git a/schema/lib/elements/he_ipv6.xsd b/schema/lib/elements/he_ipv6.xsd
index b26a5a5..8ab3cf4 100644
--- a/schema/lib/elements/he_ipv6.xsd
+++ b/schema/lib/elements/he_ipv6.xsd
@@ -25,7 +25,8 @@
               <xs:complexType>
                 <xs:simpleContent>
                   <xs:extension base="t_net_addr_ip6">
-                    <xs:attribute name="prefix" type="t_he_ipv6_prefix" use="required" default="64"/>
+                    <!-- VERY most likely "64" but we can't define a default with required. -->
+                    <xs:attribute name="prefix" type="t_he_ipv6_prefix" use="required"/>
                   </xs:extension>
                 </xs:simpleContent>
               </xs:complexType>
@@ -41,7 +42,8 @@
         <xs:complexType>
           <xs:simpleContent>
             <xs:extension base="t_net_addr_ip6">
-              <xs:attribute name="prefix" type="t_he_ipv6_prefix" use="required" default="64"/>
+              <!-- VERY most likely "64" but we can't define a default with required. -->
+              <xs:attribute name="prefix" type="t_he_ipv6_prefix" use="required"/>
             </xs:extension>
           </xs:simpleContent>
         </xs:complexType>