diff --git a/firmware/src_simtrace/card_emu.c b/firmware/src_simtrace/card_emu.c
index c74ddaf8..0887a1b9 100644
--- a/firmware/src_simtrace/card_emu.c
+++ b/firmware/src_simtrace/card_emu.c
@@ -538,6 +538,8 @@ static void set_tpdu_state(struct card_handle *ch, enum tpdu_state new_ts)
 		 * transmitter and transmit the procedure byte */
 		card_emu_uart_enable(ch->uart_chan, ENABLE_TX);
 		break;
+	default:
+		break;
 	}
 
 	ch->tpdu.state = new_ts;
@@ -692,6 +694,8 @@ static int tx_byte_tpdu(struct card_handle *ch)
 		else if (td->flags & CEMU_DATA_F_PB_AND_RX)
 			set_tpdu_state(ch, TPDU_S_WAIT_RX);
 		break;
+	default:
+		break;
 	}
 
 	/* check if the buffer has now been fully transmitted */
@@ -785,6 +789,8 @@ int card_emu_tx_byte(struct card_handle *ch)
 	case ISO_S_IN_TPDU:
 		rc = tx_byte_tpdu(ch);
 		break;
+	default:
+		break;
 	}
 
 	if (rc)