diff --git a/gnss/common/utils/default/NmeaFixInfo.cpp b/gnss/common/utils/default/NmeaFixInfo.cpp
index 43e008b..c7ee134 100644
--- a/gnss/common/utils/default/NmeaFixInfo.cpp
+++ b/gnss/common/utils/default/NmeaFixInfo.cpp
@@ -202,8 +202,15 @@
     uint32_t fixId = 0;
     double lastTimeStamp = 0;
     for (const auto& line : nmeaRecords) {
+        if (line.compare(0, strlen(GPGA_RECORD_TAG), GPGA_RECORD_TAG) != 0 &&
+            line.compare(0, strlen(GPRMC_RECORD_TAG), GPRMC_RECORD_TAG) != 0) {
+            continue;
+        }
         std::vector<std::string> sentenceValues;
         splitStr(line, COMMA_SEPARATOR, sentenceValues);
+        if (sentenceValues.size() < MIN_COL_NUM) {
+            continue;
+        }
         double currentTimeStamp = std::stof(sentenceValues[1]);
         // If see a new timestamp, report correct location.
         if ((currentTimeStamp - lastTimeStamp) > TIMESTAMP_EPSILON &&
diff --git a/gnss/common/utils/default/include/NmeaFixInfo.h b/gnss/common/utils/default/include/NmeaFixInfo.h
index 06eae7e..c96eece 100644
--- a/gnss/common/utils/default/include/NmeaFixInfo.h
+++ b/gnss/common/utils/default/include/NmeaFixInfo.h
@@ -32,6 +32,7 @@
 constexpr char LINE_SEPARATOR = '\n';
 constexpr char COMMA_SEPARATOR = ',';
 constexpr double TIMESTAMP_EPSILON = 0.001;
+constexpr int MIN_COL_NUM = 13;
 
 /** Helper class to parse and store the GNSS fix details information. */
 class NmeaFixInfo {
diff --git a/gnss/common/utils/default/include/v2_1/GnssTemplate.h b/gnss/common/utils/default/include/v2_1/GnssTemplate.h
index 79c78c3..a6e8f58 100644
--- a/gnss/common/utils/default/include/v2_1/GnssTemplate.h
+++ b/gnss/common/utils/default/include/v2_1/GnssTemplate.h
@@ -196,6 +196,7 @@
         return nullptr;
     }
     while (true) {
+        memset(inputBuffer, 0, INPUT_BUFFER_SIZE);
         bytes_read = read(mGnssFd, &inputBuffer, INPUT_BUFFER_SIZE);
         if (bytes_read <= 0) {
             break;
@@ -218,9 +219,14 @@
             auto svStatus = filterBlocklistedSatellitesV2_1(Utils::getMockSvInfoListV2_1());
             this->reportSvStatus(svStatus);
             auto currentLocation = getLocationFromHW();
-            if (mGnssFd != -1 && currentLocation != nullptr) {
+            if (mGnssFd != -1) {
                 // Only report location if the return from hardware is valid
-                this->reportLocation(*currentLocation);
+                // note that we can not merge these two "if" together, if didn't
+                // get location from hardware, we shouldn't report location, not
+                // report the "default" one.
+                if (currentLocation != nullptr) {
+                    this->reportLocation(*currentLocation);
+                }
             } else {
                 if (sGnssCallback_2_1 != nullptr || sGnssCallback_2_0 != nullptr) {
                     const auto location = Utils::getMockLocationV2_0();
@@ -259,6 +265,7 @@
     if (mGnssFd != -1) {
         close(mGnssFd);
         mGnssFd = -1;
+        mHardwareModeChecked = false;
     }
     return true;
 }