diff --git a/include/sound/ump.h b/include/sound/ump.h
index 44d2c2fd021d..91238dabe307 100644
--- a/include/sound/ump.h
+++ b/include/sound/ump.h
@@ -45,6 +45,7 @@ struct snd_ump_endpoint {
 	spinlock_t legacy_locks[2];
 	struct snd_rawmidi *legacy_rmidi;
 	struct snd_rawmidi_substream *legacy_substreams[2][SNDRV_UMP_MAX_GROUPS];
+	unsigned char legacy_mapping[SNDRV_UMP_MAX_GROUPS];
 
 	/* for legacy output; need to open the actual substream unlike input */
 	int legacy_out_opens;
diff --git a/sound/core/ump.c b/sound/core/ump.c
index d5d72473d999..cd192bec227a 100644
--- a/sound/core/ump.c
+++ b/sound/core/ump.c
@@ -984,7 +984,7 @@ static int snd_ump_legacy_open(struct snd_rawmidi_substream *substream)
 {
 	struct snd_ump_endpoint *ump = substream->rmidi->private_data;
 	int dir = substream->stream;
-	int group = substream->number;
+	int group = ump->legacy_mapping[substream->number];
 	int err;
 
 	mutex_lock(&ump->open_mutex);
@@ -1016,7 +1016,7 @@ static int snd_ump_legacy_close(struct snd_rawmidi_substream *substream)
 {
 	struct snd_ump_endpoint *ump = substream->rmidi->private_data;
 	int dir = substream->stream;
-	int group = substream->number;
+	int group = ump->legacy_mapping[substream->number];
 
 	mutex_lock(&ump->open_mutex);
 	spin_lock_irq(&ump->legacy_locks[dir]);
@@ -1123,6 +1123,34 @@ static void process_legacy_input(struct snd_ump_endpoint *ump, const u32 *src,
 	spin_unlock_irqrestore(&ump->legacy_locks[dir], flags);
 }
 
+/* Fill ump->legacy_mapping[] for groups to be used for legacy rawmidi */
+static int fill_legacy_mapping(struct snd_ump_endpoint *ump)
+{
+	struct snd_ump_block *fb;
+	unsigned int group_maps = 0;
+	int i, num;
+
+	if (ump->info.flags & SNDRV_UMP_EP_INFO_STATIC_BLOCKS) {
+		list_for_each_entry(fb, &ump->block_list, list) {
+			for (i = 0; i < fb->info.num_groups; i++)
+				group_maps |= 1U << (fb->info.first_group + i);
+		}
+		if (!group_maps)
+			ump_info(ump, "No UMP Group is found in FB\n");
+	}
+
+	/* use all groups for non-static case */
+	if (!group_maps)
+		group_maps = (1U << SNDRV_UMP_MAX_GROUPS) - 1;
+
+	num = 0;
+	for (i = 0; i < SNDRV_UMP_MAX_GROUPS; i++)
+		if (group_maps & (1U << i))
+			ump->legacy_mapping[num++] = i;
+
+	return num;
+}
+
 static void fill_substream_names(struct snd_ump_endpoint *ump,
 				 struct snd_rawmidi *rmidi, int dir)
 {
@@ -1130,7 +1158,7 @@ static void fill_substream_names(struct snd_ump_endpoint *ump,
 
 	list_for_each_entry(s, &rmidi->streams[dir].substreams, list)
 		snprintf(s->name, sizeof(s->name), "Group %d (%s)",
-			 s->number + 1, ump->info.name);
+			 ump->legacy_mapping[s->number] + 1, ump->info.name);
 }
 
 int snd_ump_attach_legacy_rawmidi(struct snd_ump_endpoint *ump,
@@ -1138,16 +1166,19 @@ int snd_ump_attach_legacy_rawmidi(struct snd_ump_endpoint *ump,
 {
 	struct snd_rawmidi *rmidi;
 	bool input, output;
-	int err;
+	int err, num;
 
-	ump->out_cvts = kcalloc(16, sizeof(*ump->out_cvts), GFP_KERNEL);
+	ump->out_cvts = kcalloc(SNDRV_UMP_MAX_GROUPS,
+				sizeof(*ump->out_cvts), GFP_KERNEL);
 	if (!ump->out_cvts)
 		return -ENOMEM;
 
+	num = fill_legacy_mapping(ump);
+
 	input = ump->core.info_flags & SNDRV_RAWMIDI_INFO_INPUT;
 	output = ump->core.info_flags & SNDRV_RAWMIDI_INFO_OUTPUT;
 	err = snd_rawmidi_new(ump->core.card, id, device,
-			      output ? 16 : 0, input ? 16 : 0,
+			      output ? num : 0, input ? num : 0,
 			      &rmidi);
 	if (err < 0) {
 		kfree(ump->out_cvts);