diff --git a/gnss/1.0/default/AGnss.cpp b/gnss/1.0/default/AGnss.cpp
index 52fdc26..29c6ddd 100644
--- a/gnss/1.0/default/AGnss.cpp
+++ b/gnss/1.0/default/AGnss.cpp
@@ -41,6 +41,7 @@
 
 AGnss::~AGnss() {
     sThreadFuncArgsList.clear();
+    sInterfaceExists = false;
 }
 
 void AGnss::statusCb(AGpsStatus* status) {
@@ -78,7 +79,10 @@
                     /*
                      * Callback to client with agnssStatusIpV4Cb.
                      */
-                    sAGnssCbIface->agnssStatusIpV4Cb(aGnssStatusIpV4);
+                    auto ret = sAGnssCbIface->agnssStatusIpV4Cb(aGnssStatusIpV4);
+                    if (!ret.isOk()) {
+                        ALOGE("%s: Unable to invoke callback", __func__);
+                    }
                     break;
                 }
             case AF_INET6:
@@ -96,7 +100,10 @@
                             &(status->addr));
                     memcpy(&(aGnssStatusIpV6.ipV6Addr[0]), in6->sin6_addr.s6_addr,
                            aGnssStatusIpV6.ipV6Addr.size());
-                    sAGnssCbIface->agnssStatusIpV6Cb(aGnssStatusIpV6);
+                    auto ret = sAGnssCbIface->agnssStatusIpV6Cb(aGnssStatusIpV6);
+                    if (!ret.isOk()) {
+                        ALOGE("%s: Unable to invoke callback", __func__);
+                    }
                     break;
                 }
              default:
@@ -117,7 +124,10 @@
         /*
          * Callback to client with agnssStatusIpV4Cb.
          */
-        sAGnssCbIface->agnssStatusIpV4Cb(aGnssStatusIpV4);
+        auto ret = sAGnssCbIface->agnssStatusIpV4Cb(aGnssStatusIpV4);
+        if (!ret.isOk()) {
+            ALOGE("%s: Unable to invoke callback", __func__);
+        }
     } else {
         ALOGE("%s: Invalid size for AGPS Status", __func__);
     }
diff --git a/gnss/1.0/default/AGnssRil.cpp b/gnss/1.0/default/AGnssRil.cpp
index 480571d..1458327 100644
--- a/gnss/1.0/default/AGnssRil.cpp
+++ b/gnss/1.0/default/AGnssRil.cpp
@@ -42,6 +42,7 @@
 
 AGnssRil::~AGnssRil() {
     sThreadFuncArgsList.clear();
+    sInterfaceExists = false;
 }
 
 void AGnssRil::requestSetId(uint32_t flags) {
@@ -50,7 +51,10 @@
         return;
     }
 
-    sAGnssRilCbIface->requestSetIdCb(flags);
+    auto ret = sAGnssRilCbIface->requestSetIdCb(flags);
+    if (!ret.isOk()) {
+        ALOGE("%s: Unable to invoke callback", __func__);
+    }
 }
 
 void AGnssRil::requestRefLoc(uint32_t /*flags*/) {
@@ -59,7 +63,10 @@
         return;
     }
 
-    sAGnssRilCbIface->requestRefLocCb();
+    auto ret = sAGnssRilCbIface->requestRefLocCb();
+    if (!ret.isOk()) {
+        ALOGE("%s: Unable to invoke callback", __func__);
+    }
 }
 
 pthread_t AGnssRil::createThreadCb(const char* name, void (*start)(void*), void* arg) {
diff --git a/gnss/1.0/default/Gnss.cpp b/gnss/1.0/default/Gnss.cpp
index a2a99a0..10024fb 100644
--- a/gnss/1.0/default/Gnss.cpp
+++ b/gnss/1.0/default/Gnss.cpp
@@ -60,6 +60,7 @@
 }
 
 Gnss::~Gnss() {
+    sInterfaceExists = false;
     sThreadFuncArgsList.clear();
 }
 
@@ -75,7 +76,10 @@
     }
 
     android::hardware::gnss::V1_0::GnssLocation gnssLocation = convertToGnssLocation(location);
-    sGnssCbIface->gnssLocationCb(gnssLocation);
+    auto ret = sGnssCbIface->gnssLocationCb(gnssLocation);
+    if (!ret.isOk()) {
+        ALOGE("%s: Unable to invoke callback", __func__);
+    }
 }
 
 void Gnss::statusCb(GpsStatus* gnssStatus) {
@@ -92,7 +96,10 @@
     IGnssCallback::GnssStatusValue status =
             static_cast<IGnssCallback::GnssStatusValue>(gnssStatus->status);
 
-    sGnssCbIface->gnssStatusCb(status);
+    auto ret = sGnssCbIface->gnssStatusCb(status);
+    if (!ret.isOk()) {
+        ALOGE("%s: Unable to invoke callback", __func__);
+    }
 }
 
 void Gnss::gnssSvStatusCb(GnssSvStatus* status) {
@@ -131,7 +138,10 @@
         svStatus.gnssSvList[i] = gnssSvInfo;
     }
 
-    sGnssCbIface->gnssSvStatusCb(svStatus);
+    auto ret = sGnssCbIface->gnssSvStatusCb(svStatus);
+    if (!ret.isOk()) {
+        ALOGE("%s: Unable to invoke callback", __func__);
+    }
 }
 
 /*
@@ -231,7 +241,10 @@
         }
     }
 
-    sGnssCbIface->gnssSvStatusCb(svStatus);
+    auto ret = sGnssCbIface->gnssSvStatusCb(svStatus);
+    if (!ret.isOk()) {
+        ALOGE("%s: Unable to invoke callback", __func__);
+    }
 }
 
 void Gnss::nmeaCb(GpsUtcTime timestamp, const char* nmea, int length) {
@@ -242,7 +255,10 @@
 
     android::hardware::hidl_string nmeaString;
     nmeaString.setToExternal(nmea, length);
-    sGnssCbIface->gnssNmeaCb(timestamp, nmeaString);
+    auto ret = sGnssCbIface->gnssNmeaCb(timestamp, nmeaString);
+    if (!ret.isOk()) {
+        ALOGE("%s: Unable to invoke callback", __func__);
+    }
 }
 
 void Gnss::setCapabilitiesCb(uint32_t capabilities) {
@@ -251,7 +267,10 @@
         return;
     }
 
-    sGnssCbIface->gnssSetCapabilitesCb(capabilities);
+    auto ret = sGnssCbIface->gnssSetCapabilitesCb(capabilities);
+    if (!ret.isOk()) {
+        ALOGE("%s: Unable to invoke callback", __func__);
+    }
 }
 
 void Gnss::acquireWakelockCb() {
@@ -298,7 +317,10 @@
             ALOGI("%s: GNSS HAL Wakelock acquired due to gps: %d, fused: %d", __func__,
                     sWakelockHeldGnss, sWakelockHeldFused);
             sWakelockHeld = true;
-            sGnssCbIface->gnssAcquireWakelockCb();
+            auto ret = sGnssCbIface->gnssAcquireWakelockCb();
+            if (!ret.isOk()) {
+                ALOGE("%s: Unable to invoke callback", __func__);
+            }
         }
     } else {
         if (sWakelockHeld) {
@@ -309,7 +331,10 @@
             ALOGW("%s: GNSS HAL Wakelock released, duplicate request", __func__);
         }
         sWakelockHeld = false;
-        sGnssCbIface->gnssReleaseWakelockCb();
+        auto ret = sGnssCbIface->gnssReleaseWakelockCb();
+        if (!ret.isOk()) {
+            ALOGE("%s: Unable to invoke callback", __func__);
+        }
     }
 }
 
@@ -319,7 +344,10 @@
         return;
     }
 
-    sGnssCbIface->gnssRequestTimeCb();
+    auto ret = sGnssCbIface->gnssRequestTimeCb();
+    if (!ret.isOk()) {
+            ALOGE("%s: Unable to invoke callback", __func__);
+    }
 }
 
 pthread_t Gnss::createThreadCb(const char* name, void (*start)(void*), void* arg) {
@@ -341,7 +369,10 @@
         .yearOfHw = info->year_of_hw
     };
 
-    sGnssCbIface->gnssSetSystemInfoCb(gnssInfo);
+    auto ret = sGnssCbIface->gnssSetSystemInfoCb(gnssInfo);
+    if (!ret.isOk()) {
+            ALOGE("%s: Unable to invoke callback", __func__);
+    }
 }
 
 
@@ -434,7 +465,10 @@
 Return<sp<IAGnssRil>> Gnss::getExtensionAGnssRil()  {
     if (mGnssIface == nullptr) {
         ALOGE("%s: Gnss interface is unavailable", __func__);
-    } else {
+        return nullptr;
+    }
+
+    if (mGnssRil == nullptr) {
         const AGpsRilInterface* agpsRilIface = static_cast<const AGpsRilInterface*>(
                 mGnssIface->get_extension(AGPS_RIL_INTERFACE));
         if (agpsRilIface == nullptr) {
@@ -449,7 +483,10 @@
 Return<sp<IGnssConfiguration>> Gnss::getExtensionGnssConfiguration()  {
     if (mGnssIface == nullptr) {
         ALOGE("%s: Gnss interface is unavailable", __func__);
-    } else {
+        return nullptr;
+    }
+
+    if (mGnssConfig == nullptr) {
         const GnssConfigurationInterface* gnssConfigIface =
                 static_cast<const GnssConfigurationInterface*>(
                         mGnssIface->get_extension(GNSS_CONFIGURATION_INTERFACE));
@@ -462,10 +499,14 @@
     }
     return mGnssConfig;
 }
+
 Return<sp<IGnssGeofencing>> Gnss::getExtensionGnssGeofencing()  {
     if (mGnssIface == nullptr) {
         ALOGE("%s: Gnss interface is unavailable", __func__);
-    } else {
+        return nullptr;
+    }
+
+    if (mGnssGeofencingIface == nullptr) {
         const GpsGeofencingInterface* gpsGeofencingIface =
                 static_cast<const GpsGeofencingInterface*>(
                         mGnssIface->get_extension(GPS_GEOFENCING_INTERFACE));
@@ -483,7 +524,10 @@
 Return<sp<IAGnss>> Gnss::getExtensionAGnss()  {
     if (mGnssIface == nullptr) {
         ALOGE("%s: Gnss interface is unavailable", __func__);
-    } else {
+        return nullptr;
+    }
+
+    if (mAGnssIface == nullptr) {
         const AGpsInterface* agpsIface = static_cast<const AGpsInterface*>(
                 mGnssIface->get_extension(AGPS_INTERFACE));
         if (agpsIface == nullptr) {
@@ -498,7 +542,10 @@
 Return<sp<IGnssNi>> Gnss::getExtensionGnssNi()  {
     if (mGnssIface == nullptr) {
         ALOGE("%s: Gnss interface is unavailable", __func__);
-    } else {
+        return nullptr;
+    }
+
+    if (mGnssNi == nullptr) {
         const GpsNiInterface* gpsNiIface = static_cast<const GpsNiInterface*>(
                 mGnssIface->get_extension(GPS_NI_INTERFACE));
         if (gpsNiIface == nullptr) {
@@ -513,7 +560,10 @@
 Return<sp<IGnssMeasurement>> Gnss::getExtensionGnssMeasurement() {
     if (mGnssIface == nullptr) {
         ALOGE("%s: Gnss interface is unavailable", __func__);
-    } else {
+        return nullptr;
+    }
+
+    if (mGnssMeasurement == nullptr) {
         const GpsMeasurementInterface* gpsMeasurementIface =
                 static_cast<const GpsMeasurementInterface*>(
                         mGnssIface->get_extension(GPS_MEASUREMENT_INTERFACE));
@@ -530,7 +580,10 @@
 Return<sp<IGnssNavigationMessage>> Gnss::getExtensionGnssNavigationMessage() {
     if (mGnssIface == nullptr) {
         ALOGE("%s: Gnss interface is unavailable", __func__);
-    } else {
+        return nullptr;
+    }
+
+    if (mGnssNavigationMessage == nullptr) {
         const GpsNavigationMessageInterface* gpsNavigationMessageIface =
                 static_cast<const GpsNavigationMessageInterface*>(
                         mGnssIface->get_extension(GPS_NAVIGATION_MESSAGE_INTERFACE));
@@ -549,7 +602,10 @@
 Return<sp<IGnssXtra>> Gnss::getExtensionXtra()  {
     if (mGnssIface == nullptr) {
         ALOGE("%s: Gnss interface is unavailable", __func__);
-    } else {
+        return nullptr;
+    }
+
+    if (mGnssXtraIface == nullptr) {
         const GpsXtraInterface* gpsXtraIface = static_cast<const GpsXtraInterface*>(
                 mGnssIface->get_extension(GPS_XTRA_INTERFACE));
 
@@ -566,7 +622,10 @@
 Return<sp<IGnssDebug>> Gnss::getExtensionGnssDebug()  {
     if (mGnssIface == nullptr) {
         ALOGE("%s: Gnss interface is unavailable", __func__);
-    } else {
+        return nullptr;
+    }
+
+    if (mGnssDebug == nullptr) {
         const GpsDebugInterface* gpsDebugIface = static_cast<const GpsDebugInterface*>(
                 mGnssIface->get_extension(GPS_DEBUG_INTERFACE));
 
@@ -583,7 +642,10 @@
 Return<sp<IGnssBatching>> Gnss::getExtensionGnssBatching()  {
     if (mGnssIface == nullptr) {
         ALOGE("%s: Gnss interface is unavailable", __func__);
-    } else {
+        return nullptr;
+    }
+
+    if (mGnssBatching == nullptr) {
         hw_module_t* module;
         const FlpLocationInterface* flpLocationIface = nullptr;
         int err = hw_get_module(FUSED_LOCATION_HARDWARE_MODULE_ID, (hw_module_t const**)&module);
diff --git a/gnss/1.0/default/GnssBatching.cpp b/gnss/1.0/default/GnssBatching.cpp
index 95c5e60..42f1473 100644
--- a/gnss/1.0/default/GnssBatching.cpp
+++ b/gnss/1.0/default/GnssBatching.cpp
@@ -103,7 +103,10 @@
         gnssLocations.push_back(convertToGnssLocation(locations[iLocation]));
     }
 
-    sGnssBatchingCbIface->gnssLocationBatchCb(gnssLocations);
+    auto ret = sGnssBatchingCbIface->gnssLocationBatchCb(gnssLocations);
+    if (!ret.isOk()) {
+        ALOGE("%s: Unable to invoke callback", __func__);
+    }
 }
 
 void GnssBatching::acquireWakelockCb() {
diff --git a/gnss/1.0/default/GnssGeofencing.cpp b/gnss/1.0/default/GnssGeofencing.cpp
index f42de42..54c4aaa 100644
--- a/gnss/1.0/default/GnssGeofencing.cpp
+++ b/gnss/1.0/default/GnssGeofencing.cpp
@@ -48,6 +48,7 @@
 
 GnssGeofencing::~GnssGeofencing() {
     sThreadFuncArgsList.clear();
+    sInterfaceExists = false;
 }
 void GnssGeofencing::gnssGfTransitionCb(int32_t geofenceId,
                                         GpsLocation* location,
@@ -64,11 +65,14 @@
     }
 
     GnssLocation gnssLocation = convertToGnssLocation(location);
-    mGnssGeofencingCbIface->gnssGeofenceTransitionCb(
+    auto ret = mGnssGeofencingCbIface->gnssGeofenceTransitionCb(
             geofenceId,
             gnssLocation,
             static_cast<IGnssGeofenceCallback::GeofenceTransition>(transition),
             timestamp);
+    if (!ret.isOk()) {
+        ALOGE("%s: Unable to invoke callback", __func__);
+    }
 }
 
 void GnssGeofencing::gnssGfStatusCb(int32_t status, GpsLocation* location) {
@@ -85,8 +89,11 @@
         gnssLocation = {};
     }
 
-    mGnssGeofencingCbIface->gnssGeofenceStatusCb(
+    auto ret = mGnssGeofencingCbIface->gnssGeofenceStatusCb(
             static_cast<IGnssGeofenceCallback::GeofenceAvailability>(status), gnssLocation);
+    if (!ret.isOk()) {
+        ALOGE("%s: Unable to invoke callback", __func__);
+    }
 }
 
 void GnssGeofencing::gnssGfAddCb(int32_t geofenceId, int32_t status) {
@@ -95,8 +102,11 @@
         return;
     }
 
-    mGnssGeofencingCbIface->gnssGeofenceAddCb(
+    auto ret = mGnssGeofencingCbIface->gnssGeofenceAddCb(
             geofenceId, static_cast<IGnssGeofenceCallback::GeofenceStatus>(status));
+    if (!ret.isOk()) {
+        ALOGE("%s: Unable to invoke callback", __func__);
+    }
 }
 
 void GnssGeofencing::gnssGfRemoveCb(int32_t geofenceId, int32_t status) {
@@ -105,8 +115,11 @@
         return;
     }
 
-    mGnssGeofencingCbIface->gnssGeofenceRemoveCb(
-      geofenceId, static_cast<IGnssGeofenceCallback::GeofenceStatus>(status));
+    auto ret = mGnssGeofencingCbIface->gnssGeofenceRemoveCb(
+            geofenceId, static_cast<IGnssGeofenceCallback::GeofenceStatus>(status));
+    if (!ret.isOk()) {
+        ALOGE("%s: Unable to invoke callback", __func__);
+    }
 }
 
 void GnssGeofencing::gnssGfPauseCb(int32_t geofenceId, int32_t status) {
@@ -115,8 +128,11 @@
         return;
     }
 
-    mGnssGeofencingCbIface->gnssGeofencePauseCb(
+    auto ret = mGnssGeofencingCbIface->gnssGeofencePauseCb(
             geofenceId, static_cast<IGnssGeofenceCallback::GeofenceStatus>(status));
+    if (!ret.isOk()) {
+        ALOGE("%s: Unable to invoke callback", __func__);
+    }
 }
 
 void GnssGeofencing::gnssGfResumeCb(int32_t geofenceId, int32_t status) {
@@ -125,8 +141,11 @@
         return;
     }
 
-    mGnssGeofencingCbIface->gnssGeofenceResumeCb(
+    auto ret = mGnssGeofencingCbIface->gnssGeofenceResumeCb(
             geofenceId, static_cast<IGnssGeofenceCallback::GeofenceStatus>(status));
+    if (!ret.isOk()) {
+        ALOGE("%s: Unable to invoke callback", __func__);
+    }
 }
 
 pthread_t GnssGeofencing::createThreadCb(const char* name, void (*start)(void*), void* arg) {
diff --git a/gnss/1.0/default/GnssMeasurement.cpp b/gnss/1.0/default/GnssMeasurement.cpp
index 67f6d8d..6c9b838 100644
--- a/gnss/1.0/default/GnssMeasurement.cpp
+++ b/gnss/1.0/default/GnssMeasurement.cpp
@@ -96,7 +96,10 @@
         .hwClockDiscontinuityCount = clockVal.hw_clock_discontinuity_count
     };
 
-    sGnssMeasureCbIface->GnssMeasurementCb(gnssData);
+    auto ret = sGnssMeasureCbIface->GnssMeasurementCb(gnssData);
+    if (!ret.isOk()) {
+        ALOGE("%s: Unable to invoke callback", __func__);
+    }
 }
 
 /*
@@ -223,7 +226,10 @@
     gnssData.clock.driftUncertaintyNsps = clockVal.drift_uncertainty_nsps;
     gnssData.clock.gnssClockFlags = clockVal.flags;
 
-    sGnssMeasureCbIface->GnssMeasurementCb(gnssData);
+    auto ret = sGnssMeasureCbIface->GnssMeasurementCb(gnssData);
+    if (!ret.isOk()) {
+        ALOGE("%s: Unable to invoke callback", __func__);
+    }
 }
 
 // Methods from ::android::hardware::gnss::V1_0::IGnssMeasurement follow.
diff --git a/gnss/1.0/default/GnssNavigationMessage.cpp b/gnss/1.0/default/GnssNavigationMessage.cpp
index c98abf6..6f509d0 100644
--- a/gnss/1.0/default/GnssNavigationMessage.cpp
+++ b/gnss/1.0/default/GnssNavigationMessage.cpp
@@ -59,7 +59,10 @@
     navigationMsg.submessageId = message->submessage_id;
     navigationMsg.data.setToExternal(message->data, message->data_length);
 
-    sGnssNavigationMsgCbIface->gnssNavigationMessageCb(navigationMsg);
+    auto ret = sGnssNavigationMsgCbIface->gnssNavigationMessageCb(navigationMsg);
+    if (!ret.isOk()) {
+        ALOGE("%s: Unable to invoke callback", __func__);
+    }
 }
 
 // Methods from ::android::hardware::gnss::V1_0::IGnssNavigationMessage follow.
diff --git a/gnss/1.0/default/GnssNi.cpp b/gnss/1.0/default/GnssNi.cpp
index ec57e8c..d17891d 100644
--- a/gnss/1.0/default/GnssNi.cpp
+++ b/gnss/1.0/default/GnssNi.cpp
@@ -41,6 +41,7 @@
 
 GnssNi::~GnssNi() {
     sThreadFuncArgsList.clear();
+    sInterfaceExists = false;
 }
 
 pthread_t GnssNi::createThreadCb(const char* name, void (*start)(void*), void* arg) {
@@ -73,7 +74,10 @@
                 static_cast<IGnssNiCallback::GnssNiEncodingType>(notification->text_encoding)
     };
 
-    sGnssNiCbIface->niNotifyCb(notificationGnss);
+    auto ret = sGnssNiCbIface->niNotifyCb(notificationGnss);
+    if (!ret.isOk()) {
+        ALOGE("%s: Unable to invoke callback", __func__);
+    }
 }
 
 // Methods from ::android::hardware::gnss::V1_0::IGnssNi follow.
diff --git a/gnss/1.0/default/GnssXtra.cpp b/gnss/1.0/default/GnssXtra.cpp
index 065bb33..d124ce1 100644
--- a/gnss/1.0/default/GnssXtra.cpp
+++ b/gnss/1.0/default/GnssXtra.cpp
@@ -35,6 +35,7 @@
 
 GnssXtra::~GnssXtra() {
     sThreadFuncArgsList.clear();
+    sInterfaceExists = false;
 }
 
 pthread_t GnssXtra::createThreadCb(const char* name, void (*start)(void*), void* arg) {
@@ -53,7 +54,10 @@
         return;
     }
 
-    sGnssXtraCbIface->downloadRequestCb();
+    auto ret = sGnssXtraCbIface->downloadRequestCb();
+    if (!ret.isOk()) {
+        ALOGE("%s: Unable to invoke callback", __func__);
+    }
 }
 
 // Methods from ::android::hardware::gnss::V1_0::IGnssXtra follow.