diff --git a/core/net/rpl/rpl-dag.c b/core/net/rpl/rpl-dag.c
index 10ad983cc..46b35e9a3 100644
--- a/core/net/rpl/rpl-dag.c
+++ b/core/net/rpl/rpl-dag.c
@@ -561,7 +561,7 @@ rpl_select_dodag(rpl_instance_t * instance, rpl_parent_t *p)
   }
 
   if(best_dag == NULL) {
-    /* No parent found : the calling function handle this problem. */
+    /* No parent found: the calling function handle this problem. */
     return NULL;
   }
 
@@ -569,7 +569,7 @@ rpl_select_dodag(rpl_instance_t * instance, rpl_parent_t *p)
     /* Remove routes installed by DAOs. */
     rpl_remove_routes(instance->current_dag);
 
-    PRINTF("RPL: New preferred DODAG : ");
+    PRINTF("RPL: New preferred DODAG: ");
     PRINT6ADDR(&best_dag->dag_id);
     PRINTF("\n");
 
@@ -986,7 +986,7 @@ rpl_local_repair(rpl_instance_t *instance)
     }
   }
 
-  rpl_reset_dio_timer(instance,1);
+  rpl_reset_dio_timer(instance, 0);
 
   RPL_STAT(rpl_stats.local_repairs++);
 }
@@ -1105,14 +1105,14 @@ rpl_process_dio(uip_ipaddr_t *from, rpl_dio_t *dio)
 
   instance = rpl_get_instance(dio->instance_id);
   if(instance == NULL) {
-    PRINTF("RPL : New instance detected : Joining...\n");
+    PRINTF("RPL: New instance detected: Joining...\n");
     rpl_join_instance(from, dio);
     return;
   }
 
   dag = rpl_get_dodag(dio->instance_id,&dio->dag_id);
   if(dag == NULL) {
-    PRINTF("RPL : Adding new dodag to known instance.\n");
+    PRINTF("RPL: Adding new dodag to known instance.\n");
     rpl_add_dodag(from,dio);
     return;
   }
@@ -1122,7 +1122,7 @@ rpl_process_dio(uip_ipaddr_t *from, rpl_dio_t *dio)
       PRINTF("RPL: Root received inconsistent DIO version number\n");
         dag->version = dio->version;
         RPL_LOLLIPOP_INCREMENT(dag->version);
-        rpl_reset_dio_timer(instance, 1);
+        rpl_reset_dio_timer(instance, 0);
     } else {
       global_repair(from, dag, dio);
     }
@@ -1132,7 +1132,7 @@ rpl_process_dio(uip_ipaddr_t *from, rpl_dio_t *dio)
       /* Inconsistency detected - someone is still on old version */
       PRINTF("RPL: old version received => inconsistency detected\n");
       if(dag->joined) {
-        rpl_reset_dio_timer(instance, 1);
+        rpl_reset_dio_timer(instance, 0);
         return;
       }
     }
@@ -1140,7 +1140,7 @@ rpl_process_dio(uip_ipaddr_t *from, rpl_dio_t *dio)
 
   if(dio->rank == INFINITE_RANK) {
     if(dag->joined) {
-      rpl_reset_dio_timer(instance, 1);
+      rpl_reset_dio_timer(instance, 0);
     }
   } else if(dio->rank < ROOT_RANK(instance)) {
     PRINTF("RPL: Ignoring DIO with too low rank: %u\n",
@@ -1150,7 +1150,7 @@ rpl_process_dio(uip_ipaddr_t *from, rpl_dio_t *dio)
 
   if(dag->rank == ROOT_RANK(instance)) {
     if(dio->rank != INFINITE_RANK) {
-        instance->dio_counter++;
+      instance->dio_counter++;
     }
     return;
   }
@@ -1199,7 +1199,7 @@ rpl_process_dio(uip_ipaddr_t *from, rpl_dio_t *dio)
   PRINTF("RPL current state: Prefered DODAG: ");
   PRINT6ADDR(&instance->current_dag->dag_id);
   PRINTF(", rank: %u, min_rank: %u, ",instance->current_dag->rank,instance->current_dag->min_rank);
-  PRINTF("p->rank : %u, p->mc.obj.etx : %u, p->link_metric : %u, instance->mc.obj.etx %u\n", p->rank, p->mc.obj.etx, p->link_metric,instance->mc.obj.etx);
+  PRINTF("p->rank: %u, p->mc.obj.etx: %u, p->link_metric: %u, instance->mc.obj.etx %u\n", p->rank, p->mc.obj.etx, p->link_metric,instance->mc.obj.etx);
 
   /* We have allocated a candidate parent; process the DIO further. */
 
diff --git a/core/net/rpl/rpl-ext-header.c b/core/net/rpl/rpl-ext-header.c
index 9ff8385fc..2f6dcfab0 100644
--- a/core/net/rpl/rpl-ext-header.c
+++ b/core/net/rpl/rpl-ext-header.c
@@ -77,7 +77,7 @@ rpl_verify_header(int uip_ext_opt_offset)
 
   instance = rpl_get_instance(UIP_EXT_HDR_OPT_RPL_BUF->instance);
   if(instance == NULL) {
-    PRINTF("RPL: Unknown instance : %u\n",
+    PRINTF("RPL: Unknown instance: %u\n",
            UIP_EXT_HDR_OPT_RPL_BUF->instance);
     return 1;
   }
@@ -90,7 +90,7 @@ rpl_verify_header(int uip_ext_opt_offset)
   if(UIP_EXT_HDR_OPT_RPL_BUF->flags & RPL_HDR_OPT_DOWN) {
     PRINTF("RPL: Packet going down :\n");
     if(UIP_EXT_HDR_OPT_RPL_BUF->senderrank > instance->current_dag->rank) {
-      PRINTF("RPL: Loop detected : Sender rank > our rank\n");
+      PRINTF("RPL: Loop detected: Sender rank > our rank\n");
       if(UIP_EXT_HDR_OPT_RPL_BUF->flags & RPL_HDR_OPT_RANK_ERR) {
         PRINTF("RPL: Loop detected !\n");
         /* We should try to repair it, not implemented for the moment */
@@ -103,7 +103,7 @@ rpl_verify_header(int uip_ext_opt_offset)
   } else {
     PRINTF("RPL: Packet going up :");
     if(UIP_EXT_HDR_OPT_RPL_BUF->senderrank < instance->current_dag->rank) {
-      PRINTF("RPL: Rank error : Sender rank < our rank\n");
+      PRINTF("RPL: Rank error: Sender rank < our rank\n");
       if(UIP_EXT_HDR_OPT_RPL_BUF->flags & RPL_HDR_OPT_RANK_ERR) {
         PRINTF("RPL: Loop detected !\n");
         /* We should try to repair it, not implemented for the moment */
@@ -236,7 +236,7 @@ rpl_add_header(rpl_instance_t *instance, int down)
   uip_ext_opt_offset = 2;
 
   if(instance == NULL || !instance->used || !instance->current_dag->joined) {
-    PRINTF("Unable to add RPL hop-by-hop extension header : incorrect instance\n");
+    PRINTF("Unable to add RPL hop-by-hop extension header: incorrect instance\n");
     return 0;
   }
 
diff --git a/core/net/rpl/rpl-icmp6.c b/core/net/rpl/rpl-icmp6.c
index 54049b130..9414ae3dd 100644
--- a/core/net/rpl/rpl-icmp6.c
+++ b/core/net/rpl/rpl-icmp6.c
@@ -233,7 +233,7 @@ dio_input(void)
 
   PRINTF("RPL: Incoming DIO DODAG ");
   PRINT6ADDR(&dio.dag_id);
-  PRINTF("  preference : %u\n",dio.preference);
+  PRINTF(", preference: %u\n", dio.preference);
 
   /* Check if there are any DIO suboptions. */
   for(; i < buffer_length; i += len) {
diff --git a/core/net/rpl/rpl-timers.c b/core/net/rpl/rpl-timers.c
index c86618f3c..aafd9e734 100644
--- a/core/net/rpl/rpl-timers.c
+++ b/core/net/rpl/rpl-timers.c
@@ -178,7 +178,8 @@ void
 rpl_reset_dio_timer(rpl_instance_t *instance, uint8_t force)
 {
 #if !RPL_LEAF_ONLY
-  /* only reset if not just reset or started */
+  /* Do not reset if we are already on the minimum interval,
+     unless forced to do so. */
   if(force || instance->dio_intcurrent > instance->dio_intmin) {
     instance->dio_counter = 0;
     instance->dio_intcurrent = instance->dio_intmin;
@@ -197,8 +198,8 @@ handle_dao_timer(void *ptr)
 
   instance = (rpl_instance_t *)ptr;
 
-  if (!dio_send_ok && uip_ds6_get_link_local(ADDR_PREFERRED) == NULL) {
-    PRINTF("RPL: Postpone DAO transmission... \n");
+  if(!dio_send_ok && uip_ds6_get_link_local(ADDR_PREFERRED) == NULL) {
+    PRINTF("RPL: Postpone DAO transmission\n");
     ctimer_set(&instance->dao_timer, CLOCK_SECOND, handle_dao_timer, instance);
     return;
   }