diff --git a/core/LocAdapterBase.cpp b/core/LocAdapterBase.cpp
index 1b844e57..1e91cf83 100644
--- a/core/LocAdapterBase.cpp
+++ b/core/LocAdapterBase.cpp
@@ -43,13 +43,20 @@ namespace loc_core {
 // the right locApi should get created.
 LocAdapterBase::LocAdapterBase(const LOC_API_ADAPTER_EVENT_MASK_T mask,
                                ContextBase* context, bool isMaster,
-                               LocAdapterProxyBase *adapterProxyBase) :
+                               LocAdapterProxyBase *adapterProxyBase,
+                               bool waitForDoneInit) :
     mIsMaster(isMaster), mEvtMask(mask), mContext(context),
     mLocApi(context->getLocApi()), mLocAdapterProxyBase(adapterProxyBase),
     mMsgTask(context->getMsgTask()),
     mIsEngineCapabilitiesKnown(ContextBase::sIsEngineCapabilitiesKnown)
 {
-    mLocApi->addAdapter(this);
+    LOC_LOGd("waitForDoneInit: %d", waitForDoneInit);
+    if (!waitForDoneInit) {
+        mLocApi->addAdapter(this);
+        mAdapterAdded = true;
+    } else {
+        mAdapterAdded = false;
+    }
 }
 
 uint32_t LocAdapterBase::mSessionIdCounter(1);
diff --git a/core/LocAdapterBase.h b/core/LocAdapterBase.h
index 909b6fea..7ca3ecda 100644
--- a/core/LocAdapterBase.h
+++ b/core/LocAdapterBase.h
@@ -70,9 +70,11 @@ protected:
     LocApiBase* mLocApi;
     LocAdapterProxyBase* mLocAdapterProxyBase;
     const MsgTask* mMsgTask;
+    bool mAdapterAdded;
+
     inline LocAdapterBase(const MsgTask* msgTask) :
         mIsMaster(false), mEvtMask(0), mContext(NULL), mLocApi(NULL),
-        mLocAdapterProxyBase(NULL), mMsgTask(msgTask) {}
+        mLocAdapterProxyBase(NULL), mMsgTask(msgTask), mAdapterAdded(false) {}
 
     /* ==== CLIENT ========================================================================= */
     typedef std::map<LocationAPI*, LocationCallbacks> ClientDataMap;
@@ -89,9 +91,27 @@ protected:
 
 public:
     inline virtual ~LocAdapterBase() { mLocApi->removeAdapter(this); }
+    // When waitForDoneInit is not specified or specified as false,
+    // handleEngineUpEvent may be called on the child adapter object from
+    // a different thread before the constructor of the child
+    // object finishes.
+    //
+    // If the handleEngineUpEvent relies on member variables of the constructor
+    // of the child adapter to be initialized first, we need to specify the
+    // waitForDoneInit to *TRUE* to delay handleEngineUpEvent to get called
+    // until when the child adapter finishes its initialization and notify
+    // LocAdapterBase via doneInit method.
     LocAdapterBase(const LOC_API_ADAPTER_EVENT_MASK_T mask,
                    ContextBase* context, bool isMaster = false,
-                   LocAdapterProxyBase *adapterProxyBase = NULL);
+                   LocAdapterProxyBase *adapterProxyBase = NULL,
+                   bool waitForDoneInit = false);
+
+    inline void doneInit() {
+        if (!mAdapterAdded) {
+            mLocApi->addAdapter(this);
+            mAdapterAdded = true;
+        }
+    }
 
     inline LOC_API_ADAPTER_EVENT_MASK_T
         checkMask(LOC_API_ADAPTER_EVENT_MASK_T mask) const {
diff --git a/gnss/GnssAdapter.cpp b/gnss/GnssAdapter.cpp
index 980d4895..11f6777e 100644
--- a/gnss/GnssAdapter.cpp
+++ b/gnss/GnssAdapter.cpp
@@ -65,9 +65,10 @@ static void agpsCloseResultCb (bool isSuccess, AGpsExtType agpsType, void* userD
 GnssAdapter::GnssAdapter() :
     LocAdapterBase(0,
                    LocContext::getLocContext(NULL,
-                                                   NULL,
-                                                   LocContext::mLocationHalName,
-                                                   false), true, nullptr),
+                                             NULL,
+                                             LocContext::mLocationHalName,
+                                             false),
+                   true, nullptr, true),
     mEngHubProxy(new EngineHubProxyBase()),
     mLocPositionMode(),
     mGnssSvIdUsedInPosition(),
@@ -127,6 +128,10 @@ GnssAdapter::GnssAdapter() :
     readConfigCommand();
     initDefaultAgpsCommand();
     initEngHubProxyCommand();
+
+    // at last step, let us inform adapater base that we are done
+    // with initialization, e.g.: ready to process handleEngineUpEvent
+    doneInit();
 }
 
 void