diff --git a/examples/Makefile-posix b/examples/Makefile-posix
index 74e940e4b..7a083e5b3 100644
--- a/examples/Makefile-posix
+++ b/examples/Makefile-posix
@@ -60,6 +60,7 @@ SNTP_CLIENT                    ?= 1
 UDP_FORWARD                    ?= 1
 
 COMMONCFLAGS                   := \
+    -g                            \
     $(NULL)
 
 # If the user has asserted COVERAGE, alter the configuration options
@@ -80,7 +81,6 @@ configure_OPTIONS               = \
 ifneq ($(DEBUG),1)
 COMMONCFLAGS                   += \
     -O2                           \
-    -g                            \
     $(NULL)
 endif
 
diff --git a/examples/common-switches.mk b/examples/common-switches.mk
index 2152d3a0b..3eed5b555 100644
--- a/examples/common-switches.mk
+++ b/examples/common-switches.mk
@@ -169,7 +169,7 @@ configure_OPTIONS              += --enable-sntp-client
 endif
 
 ifeq ($(TIME_SYNC),1)
-COMMONCFLAGS                   += -DPENTHREAD_CONFIG_ENABLE_TIME_SYNC=1
+COMMONCFLAGS                   += -DOPENTHREAD_CONFIG_ENABLE_TIME_SYNC=1 -DOPENTHREAD_CONFIG_HEADER_IE_SUPPORT=1
 endif
 
 ifeq ($(UDP_FORWARD),1)
diff --git a/src/core/thread/mle_router.cpp b/src/core/thread/mle_router.cpp
index 01d0de752..f63d65e20 100644
--- a/src/core/thread/mle_router.cpp
+++ b/src/core/thread/mle_router.cpp
@@ -663,13 +663,16 @@ otError MleRouter::HandleLinkRequest(const Message &aMessage, const Ip6::Message
     }
 
 #if OPENTHREAD_CONFIG_ENABLE_TIME_SYNC
-    if (Tlv::GetTlv(aMessage, Tlv::kTimeRequest, sizeof(timeRequest), timeRequest) == OT_ERROR_NONE)
+    if (neighbor != NULL)
     {
-        neighbor->SetTimeSyncEnabled(true);
-    }
-    else
-    {
-        neighbor->SetTimeSyncEnabled(false);
+        if (Tlv::GetTlv(aMessage, Tlv::kTimeRequest, sizeof(timeRequest), timeRequest) == OT_ERROR_NONE)
+        {
+            neighbor->SetTimeSyncEnabled(true);
+        }
+        else
+        {
+            neighbor->SetTimeSyncEnabled(false);
+        }
     }
 #endif
 
@@ -745,7 +748,7 @@ otError MleRouter::SendLinkAccept(const Ip6::MessageInfo &aMessageInfo,
     }
 
 #if OPENTHREAD_CONFIG_ENABLE_TIME_SYNC
-    if (aNeighbor->IsTimeSyncEnabled())
+    if (aNeighbor != NULL && aNeighbor->IsTimeSyncEnabled())
     {
         message->SetTimeSync(true);
     }