diff --git a/sound/firewire/amdtp-am824.c b/sound/firewire/amdtp-am824.c
index fd5d6b8ac557..99c567ded7a3 100644
--- a/sound/firewire/amdtp-am824.c
+++ b/sound/firewire/amdtp-am824.c
@@ -315,12 +315,16 @@ static void read_midi_messages(struct amdtp_stream *s,
 			       __be32 *buffer, unsigned int frames)
 {
 	struct amdtp_am824 *p = s->protocol;
-	unsigned int f, port;
 	int len;
 	u8 *b;
+	int f;
 
 	for (f = 0; f < frames; f++) {
-		port = (8 - s->ctx_data.tx.first_dbc + s->data_block_counter + f) % 8;
+		unsigned int port = f;
+
+		if (!(s->flags & CIP_UNALIGHED_DBC))
+			port += s->data_block_counter;
+		port %= 8;
 		b = (u8 *)&buffer[p->midi_position];
 
 		len = b[0] - 0x80;
diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c
index 4d71d74707cf..fc1e8e5b9429 100644
--- a/sound/firewire/amdtp-stream.c
+++ b/sound/firewire/amdtp-stream.c
@@ -584,8 +584,7 @@ static int check_cip_header(struct amdtp_stream *s, const __be32 *buf,
 	    s->data_block_counter != UINT_MAX)
 		*dbc = s->data_block_counter;
 
-	if (((s->flags & CIP_SKIP_DBC_ZERO_CHECK) &&
-	     *dbc == s->ctx_data.tx.first_dbc) ||
+	if ((*dbc == 0x00 && (s->flags & CIP_SKIP_DBC_ZERO_CHECK)) ||
 	    s->data_block_counter == UINT_MAX) {
 		lost = false;
 	} else if (!(s->flags & CIP_DBC_IS_END_EVENT)) {
diff --git a/sound/firewire/amdtp-stream.h b/sound/firewire/amdtp-stream.h
index 3942894c11ac..5d611122312b 100644
--- a/sound/firewire/amdtp-stream.h
+++ b/sound/firewire/amdtp-stream.h
@@ -33,6 +33,8 @@
  * @CIP_HEADER_WITHOUT_EOH: Only for in-stream. CIP Header doesn't include
  *	valid EOH.
  * @CIP_NO_HEADERS: a lack of headers in packets
+ * @CIP_UNALIGHED_DBC: Only for in-stream. The value of dbc is not alighed to
+ *	the value of current SYT_INTERVAL; e.g. initial value is not zero.
  */
 enum cip_flags {
 	CIP_NONBLOCKING		= 0x00,
@@ -45,6 +47,7 @@ enum cip_flags {
 	CIP_JUMBO_PAYLOAD	= 0x40,
 	CIP_HEADER_WITHOUT_EOH	= 0x80,
 	CIP_NO_HEADER		= 0x100,
+	CIP_UNALIGHED_DBC	= 0x200,
 };
 
 /**
@@ -119,8 +122,6 @@ struct amdtp_stream {
 			// Fixed interval of dbc between previos/current
 			// packets.
 			unsigned int dbc_interval;
-			// Indicate the value of dbc field in a first packet.
-			unsigned int first_dbc;
 		} tx;
 		struct {
 			// To calculate CIP data blocks and tstamp.
diff --git a/sound/firewire/fireworks/fireworks_stream.c b/sound/firewire/fireworks/fireworks_stream.c
index e659a0b89ba5..385fc9686365 100644
--- a/sound/firewire/fireworks/fireworks_stream.c
+++ b/sound/firewire/fireworks/fireworks_stream.c
@@ -146,7 +146,7 @@ int snd_efw_stream_init_duplex(struct snd_efw *efw)
 	    (efw->firmware_version == 0x5070000 ||
 	     efw->firmware_version == 0x5070300 ||
 	     efw->firmware_version == 0x5080000))
-		efw->tx_stream.ctx_data.tx.first_dbc = 0x02;
+		efw->tx_stream.flags |= CIP_UNALIGHED_DBC;
 	/* AudioFire9 always reports wrong dbs. */
 	if (efw->is_af9)
 		efw->tx_stream.flags |= CIP_WRONG_DBS;