diff --git a/master/mailbox.c b/master/mailbox.c
index 214b39ba..dd6f6148 100644
--- a/master/mailbox.c
+++ b/master/mailbox.c
@@ -238,8 +238,8 @@ uint8_t *ec_slave_mbox_simple_receive(const ec_slave_t *slave, /**< slave */
     }
 
     if (unlikely(slave->master->debug_level) > 1)
-        EC_DBG("Mailbox receive took %ius.\n", ((u32) (end - start) * 1000
-                                                / cpu_khz));
+        EC_DBG("Mailbox receive took %ius.\n",
+               ((unsigned int) (end - start) * 1000 / cpu_khz));
 
     return ec_slave_mbox_fetch(slave, datagram, type, size);
 }
diff --git a/master/master.c b/master/master.c
index 15042d01..dfa399dc 100644
--- a/master/master.c
+++ b/master/master.c
@@ -394,7 +394,7 @@ void ec_master_send_datagrams(ec_master_t *master /**< EtherCAT master */)
     if (unlikely(master->debug_level > 0)) {
         t_end = get_cycles();
         EC_DBG("ec_master_send_datagrams sent %i frames in %ius.\n",
-               frame_count, (u32) (t_end - t_start) * 1000 / cpu_khz);
+               frame_count, (unsigned int) (t_end - t_start) * 1000 / cpu_khz);
     }
 }