diff --git a/master/ethernet.c b/master/ethernet.c
index 316dd1309e7eef5a1c6e838fe9472de684537099..0aa75d1fe286ab4f1ceeb2c2e6b180ae093ca0f3 100644
--- a/master/ethernet.c
+++ b/master/ethernet.c
@@ -362,7 +362,7 @@ void ec_eoe_state_rx_check(ec_eoe_t *eoe /**< EoE handler */)
 void ec_eoe_state_rx_fetch(ec_eoe_t *eoe /**< EoE handler */)
 {
     size_t rec_size, data_size;
-    uint8_t *data, frame_type, last_fragment, time_appended, mbox_type;
+    uint8_t *data, frame_type, last_fragment, time_appended, mbox_prot;
     uint8_t frame_number, fragment_offset, fragment_number;
     off_t offset;
 #if EOE_DEBUG_LEVEL > 1
@@ -376,13 +376,13 @@ void ec_eoe_state_rx_fetch(ec_eoe_t *eoe /**< EoE handler */)
     }
 
     if (!(data = ec_slave_mbox_fetch(eoe->slave, &eoe->datagram,
-                                     &mbox_type, &rec_size))) {
+                                     &mbox_prot, &rec_size))) {
         eoe->stats.rx_errors++;
         eoe->state = ec_eoe_state_tx_start;
         return;
     }
 
-    if (mbox_type != 0x02) {
+    if (mbox_prot != 0x02) { // EoE
         eoe->stats.rx_errors++;
         eoe->state = ec_eoe_state_tx_start;
         return;
diff --git a/master/fsm.c b/master/fsm.c
index 6a35929a5b73c524d210cceb13904d0c115c5f7d..7792750714a3bd773e9dd2c0ddecf3a7903c32fe 100644
--- a/master/fsm.c
+++ b/master/fsm.c
@@ -2142,7 +2142,7 @@ void ec_fsm_coe_down_response(ec_fsm_t *fsm /**< finite state machine */)
 {
     ec_datagram_t *datagram = &fsm->datagram;
     ec_slave_t *slave = fsm->slave;
-    uint8_t *data, mbox_type;
+    uint8_t *data, mbox_prot;
     size_t rec_size;
     ec_sdo_data_t *sdodata = fsm->sdodata;
 
@@ -2154,18 +2154,14 @@ void ec_fsm_coe_down_response(ec_fsm_t *fsm /**< finite state machine */)
     }
 
     if (!(data = ec_slave_mbox_fetch(slave, datagram,
-				     &mbox_type, &rec_size))) {
+				     &mbox_prot, &rec_size))) {
         fsm->coe_state = ec_fsm_error;
         return;
     }
 
-    if (mbox_type != 0x03) {
-        EC_WARN("Received mailbox protocol 0x%02X as a response."
-	      " Trying again.\n", mbox_type);
-        fsm->coe_start = get_cycles();
-        ec_slave_mbox_prepare_check(slave, datagram); // can not fail.
-	ec_master_queue_datagram(fsm->master, datagram);
-	fsm->coe_state = ec_fsm_coe_down_check;
+    if (mbox_prot != 0x03) { // CoE
+        EC_WARN("Received mailbox protocol 0x%02X as response.\n", mbox_prot);
+        fsm->coe_state = ec_fsm_error;
 	return;
     }