diff --git a/src/core/ipv6/nd6.c b/src/core/ipv6/nd6.c
index 1e7c94ce..d65ed4e1 100644
--- a/src/core/ipv6/nd6.c
+++ b/src/core/ipv6/nd6.c
@@ -697,7 +697,7 @@ nd6_input(struct pbuf *p, struct netif *inp)
 #if LWIP_ND6_ALLOW_RA_UPDATES
           if (inp->mtu) {
             /* don't set the mtu for IPv6 higher than the netif driver supports */
-            inp->mtu6 = LWIP_MIN(inp->mtu, (u16_t)mtu32);
+            inp->mtu6 = LWIP_MIN(LWIP_MIN(inp->mtu, inp->mtu6), (u16_t)mtu32);
           } else {
             inp->mtu6 = (u16_t)mtu32;
           }
diff --git a/src/core/netif.c b/src/core/netif.c
index 15200a27..e95cb672 100644
--- a/src/core/netif.c
+++ b/src/core/netif.c
@@ -1031,6 +1031,10 @@ netif_set_link_down(struct netif *netif)
 
   if (netif->flags & NETIF_FLAG_LINK_UP) {
     netif_clear_flags(netif, NETIF_FLAG_LINK_UP);
+#if LWIP_IPV6 && LWIP_ND6_ALLOW_RA_UPDATES
+    netif->mtu6 = netif->mtu;
+#endif
+
     NETIF_LINK_CALLBACK(netif);
 #if LWIP_NETIF_EXT_STATUS_CALLBACK
     {