diff --git a/ril_subscription.conf b/ril_subscription.conf
index 0b2ba26..6ccf37b 100644
--- a/ril_subscription.conf
+++ b/ril_subscription.conf
@@ -371,3 +371,10 @@ socket=/dev/socket/rild
 # Default 30000
 #
 #cellInfoIntervalLongMs=30000
+
+# Configure the ril request originated in ril_voicecall_set_udub. Some
+# devices like the Volla phone halts the modem when asking if the user
+# is busy through this function. This produces that, if you cancel an
+# awaiting call because of an on going one, both calls will be hang up.
+#
+#rilRequestOnSetUdub=13
diff --git a/src/ril_plugin.c b/src/ril_plugin.c
index c9211ed..e98b071 100644
--- a/src/ril_plugin.c
+++ b/src/ril_plugin.c
@@ -27,6 +27,7 @@
 #include "ril_vendor.h"
 #include "ril_devmon.h"
 #include "ril_log.h"
+#include "ril-constants.h"
 
 #include <ofono/slot.h>
 #include <ofono/storage.h>
@@ -100,6 +101,7 @@
 #define RILMODEM_DEFAULT_SLOT_FLAGS OFONO_SLOT_NO_FLAGS
 #define RILMODEM_DEFAULT_CELL_INFO_INTERVAL_SHORT_MS (2000) /* 2 sec */
 #define RILMODEM_DEFAULT_CELL_INFO_INTERVAL_LONG_MS  (30000) /* 30 sec */
+#define RILMODEM_DEFAULT_RIL_REQUEST_ON_SET_UDUB     RIL_REQUEST_UDUB
 
 /* RIL socket transport name and parameters */
 #define RIL_TRANSPORT_MODEM                 "modem"
@@ -160,6 +162,7 @@
 #define RILCONF_DEVMON                      "deviceStateTracking"
 #define RILCONF_CELL_INFO_INTERVAL_SHORT_MS "cellInfoIntervalShortMs"
 #define RILCONF_CELL_INFO_INTERVAL_LONG_MS  "cellInfoIntervalLongMs"
+#define RILCONF_RIL_REQUEST_ON_SET_UDUB     "rilRequestOnSetUdub"
 
 /* Modem error ids */
 #define RIL_ERROR_ID_RILD_RESTART           "rild-restart"
@@ -1278,6 +1281,8 @@ static RilSlot *ril_plugin_slot_new_take(char *transport,
 				RILMODEM_DEFAULT_CELL_INFO_INTERVAL_SHORT_MS;
 	config->cell_info_interval_long_ms =
 				RILMODEM_DEFAULT_CELL_INFO_INTERVAL_LONG_MS;
+	config->ril_request_on_set_udub =
+				RILMODEM_DEFAULT_RIL_REQUEST_ON_SET_UDUB;
 	slot->timeout = RILMODEM_DEFAULT_TIMEOUT;
 	slot->sim_flags = RILMODEM_DEFAULT_SIM_FLAGS;
 	slot->slot_flags = RILMODEM_DEFAULT_SLOT_FLAGS;
@@ -1806,6 +1811,14 @@ static RilSlot *ril_plugin_parse_config_group(GKeyFile *file,
 				group, config->cell_info_interval_long_ms);
 	}
 
+	/* rilRequestOnSetUdub */
+	if (ril_config_get_integer(file, group,
+				RILCONF_RIL_REQUEST_ON_SET_UDUB,
+				&config->ril_request_on_set_udub)) {
+		DBG("%s: " RILCONF_RIL_REQUEST_ON_SET_UDUB " %d",
+				group, config->ril_request_on_set_udub);
+	}
+
 	/* Replace devmon with a new one with applied settings */
 	ril_devmon_free(slot->devmon);
 	slot->devmon = NULL;
diff --git a/src/ril_types.h b/src/ril_types.h
index 3198a3e..6ba2c94 100644
--- a/src/ril_types.h
+++ b/src/ril_types.h
@@ -81,6 +81,7 @@ struct ril_slot_config {
 	GUtilInts *remote_hangup_reasons;
 	int cell_info_interval_short_ms;
 	int cell_info_interval_long_ms;
+	int ril_request_on_set_udub;
 };
 
 /* Some values copied from ofono's internal common.h */
diff --git a/src/ril_voicecall.c b/src/ril_voicecall.c
index ed3856b..cde8579 100644
--- a/src/ril_voicecall.c
+++ b/src/ril_voicecall.c
@@ -56,6 +56,7 @@ struct ril_voicecall {
 	gulong supp_svc_notification_id;
 	gulong ringback_tone_event_id;
 	gulong ecclist_change_id;
+	int ril_request_on_set_udub;
 };
 
 struct ril_voicecall_request_data {
@@ -856,8 +857,10 @@ static void ril_voicecall_release_all_active(struct ofono_voicecall *vc,
 static void ril_voicecall_set_udub(struct ofono_voicecall *vc,
 					ofono_voicecall_cb_t cb, void *data)
 {
+	struct ril_voicecall *vd = ril_voicecall_get_data(vc);
 	DBG("");
-	ril_voicecall_request(RIL_REQUEST_UDUB, vc, NULL, cb, data);
+	ril_voicecall_request(vd->ril_request_on_set_udub,
+						vc, NULL, cb, data);
 }
 
 static void ril_voicecall_enable_supp_svc(struct ril_voicecall *vd)
@@ -955,6 +958,9 @@ static int ril_voicecall_probe(struct ofono_voicecall *vc, unsigned int vendor,
 	if (modem->ecclist_file) {
 		vd->ecclist = ril_ecclist_new(modem->ecclist_file);
 	}
+	if (cfg->ril_request_on_set_udub) {
+	    vd->ril_request_on_set_udub = cfg->ril_request_on_set_udub;
+	}
 	ril_voicecall_clear_dtmf_queue(vd);
 	ofono_voicecall_set_data(vc, vd);
 	gutil_idle_queue_add(vd->idleq, ril_voicecall_register, vd);