diff --git a/os/net/app-layer/coap/coap-engine.c b/os/net/app-layer/coap/coap-engine.c
index fb85b5b15..cbfa70ee9 100644
--- a/os/net/app-layer/coap/coap-engine.c
+++ b/os/net/app-layer/coap/coap-engine.c
@@ -199,10 +199,18 @@ coap_receive(const coap_endpoint_t *src,
           new_offset = block_offset;
         }
 
-        /* call CoAP framework and check if found and allowed */
-        status = call_service(message, response,
-                              transaction->message + COAP_MAX_HEADER_SIZE,
-                              block_size, &new_offset);
+        if(new_offset < 0) {
+          LOG_DBG("Blockwise: block request offset overflow\n");
+          coap_status_code = BAD_OPTION_4_02;
+          coap_error_message = "BlockOutOfScope";
+          status = COAP_HANDLER_STATUS_CONTINUE;
+        } else {
+          /* call CoAP framework and check if found and allowed */
+          status = call_service(message, response,
+                                transaction->message + COAP_MAX_HEADER_SIZE,
+                                block_size, &new_offset);
+        }
+
         if(status != COAP_HANDLER_STATUS_CONTINUE) {
 
             if(coap_status_code == NO_ERROR) {
diff --git a/os/net/app-layer/coap/coap.c b/os/net/app-layer/coap/coap.c
index 42a2d5cef..c28e2d8b5 100644
--- a/os/net/app-layer/coap/coap.c
+++ b/os/net/app-layer/coap/coap.c
@@ -1115,13 +1115,10 @@ coap_set_header_size1(coap_message_t *coap_pkt, uint32_t size)
 int
 coap_get_payload(coap_message_t *coap_pkt, const uint8_t **payload)
 {
-  if(coap_pkt->payload) {
+  if(payload != NULL) {
     *payload = coap_pkt->payload;
-    return coap_pkt->payload_len;
-  } else {
-    *payload = NULL;
-    return 0;
   }
+  return coap_pkt->payload != NULL ? coap_pkt->payload_len : 0;
 }
 int
 coap_set_payload(coap_message_t *coap_pkt, const void *payload, size_t length)
diff --git a/os/net/routing/rpl-lite/rpl-dag.c b/os/net/routing/rpl-lite/rpl-dag.c
index 5a9a160b6..68d9e7aaa 100644
--- a/os/net/routing/rpl-lite/rpl-dag.c
+++ b/os/net/routing/rpl-lite/rpl-dag.c
@@ -397,9 +397,15 @@ process_dio_from_current_dag(uip_ipaddr_t *from, rpl_dio_t *dio)
     return;
   }
 
-  /* If the DIO sender is on an older version of the DAG, ignore it. The node
-  will eventually hear the global repair and catch up. */
+  /* If the DIO sender is on an older version of the DAG, do not process it
+   * further. The sender will eventually hear the global repair and catch up. */
   if(rpl_lollipop_greater_than(curr_instance.dag.version, dio->version)) {
+    if(dio->rank == ROOT_RANK) {
+      /* Before returning, if the DIO was from the root, an old DAG versions
+       * likely incidates a root reboot. Reset our DIO timer to make sure the
+       * root hears our version ASAP, and in turn triggers a global repair. */
+      rpl_timers_dio_reset("Heard old version from root");
+    }
     return;
   }
 
@@ -414,10 +420,12 @@ process_dio_from_current_dag(uip_ipaddr_t *from, rpl_dio_t *dio)
    * Must come first, as it might remove all neighbors, and we then need
    * to re-add this source of the DIO to the neighbor table */
   if(rpl_lollipop_greater_than(dio->version, curr_instance.dag.version)) {
-    if(curr_instance.dag.rank == ROOT_RANK) { /* The root should not hear newer versions */
+    if(curr_instance.dag.rank == ROOT_RANK) {
+      /* The root should not hear newer versions unless it just rebooted */
       LOG_ERR("inconsistent DIO version (current: %u, received: %u), initiate global repair\n",
           curr_instance.dag.version, dio->version);
-      curr_instance.dag.version = dio->version; /* Update version and trigger global repair */
+      /* Update version and trigger global repair */
+      curr_instance.dag.version = dio->version;
       rpl_global_repair("Inconsistent DIO version");
     } else {
       LOG_WARN("new DIO version (current: %u, received: %u), apply global repair\n",