--- a/dom/telephony/Telephony.cpp
+++ b/dom/telephony/Telephony.cpp
@@ -372,20 +372,24 @@ Telephony::HandleCallInfo(nsITelephonyCa
     call->UpdateSwitchable(isSwitchable);
     call->UpdateMergeable(isMergeable);
 
     nsAutoString number;
     aInfo->GetNumber(number);
     nsRefPtr<TelephonyCallId> id = call->Id();
     id->UpdateNumber(number);
 
+    nsAutoString disconnectedReason;
+    aInfo->GetDisconnectedReason(disconnectedReason);
+
     // State changed.
     if (call->CallState() != callState) {
       if (callState == nsITelephonyService::CALL_STATE_DISCONNECTED) {
-        call->ChangeStateInternal(callState, true);
+        call->UpdateDisconnectedReason(disconnectedReason);
+        call->ChangeState(nsITelephonyService::CALL_STATE_DISCONNECTED);
         return NS_OK;
       }
 
       // We don't fire the statechange event on a call in conference here.
       // Instead, the event will be fired later in
       // TelephonyCallGroup::ChangeState(). Thus the sequence of firing the
       // statechange events is guaranteed: first on TelephonyCallGroup then on
       // individual TelephonyCall objects.

--- a/dom/telephony/TelephonyCall.cpp
+++ b/dom/telephony/TelephonyCall.cpp
@@ -129,17 +129,16 @@ TelephonyCall::ChangeStateInternal(uint1
   if (aCallState == nsITelephonyService::CALL_STATE_DISCONNECTED) {
     NS_ASSERTION(mLive, "Should be live!");
     mLive = false;
     if (mGroup) {
       mGroup->RemoveCall(this);
     } else {
       mTelephony->RemoveCall(this);
     }
-    UpdateDisconnectedReason(NS_LITERAL_STRING("NormalCallClearingError"));
   } else if (!mLive) {
     mLive = true;
     if (mGroup) {
       mGroup->AddCall(this);
     } else {
       mTelephony->AddCall(this);
     }
   }
@@ -206,26 +205,33 @@ TelephonyCall::NotifyError(const nsAStri
   if (NS_FAILED(rv)) {
     NS_WARNING("Failed to dispatch error event!");
   }
 }
 
 void
 TelephonyCall::UpdateDisconnectedReason(const nsAString& aDisconnectedReason)
 {
-  NS_ASSERTION(Substring(aDisconnectedReason, aDisconnectedReason.Length() - 5).EqualsLiteral("Error"),
+  NS_ASSERTION(Substring(aDisconnectedReason,
+                         aDisconnectedReason.Length() - 5).EqualsLiteral("Error"),
                "Disconnected reason should end with 'Error'");
 
-  if (mDisconnectedReason.IsNull()) {
-    // There is no 'Error' suffix in the corresponding enum. We should skip
-    // that part for comparison.
-    CONVERT_STRING_TO_NULLABLE_ENUM(
-        Substring(aDisconnectedReason, 0, aDisconnectedReason.Length() - 5),
-        TelephonyCallDisconnectedReason,
-        mDisconnectedReason);
+  if (!mDisconnectedReason.IsNull()) {
+    return;
+  }
+
+  // There is no 'Error' suffix in the corresponding enum. We should skip
+  // that part for comparison.
+  CONVERT_STRING_TO_NULLABLE_ENUM(
+      Substring(aDisconnectedReason, 0, aDisconnectedReason.Length() - 5),
+      TelephonyCallDisconnectedReason,
+      mDisconnectedReason);
+
+  if (!aDisconnectedReason.EqualsLiteral("NormalCallClearingError")) {
+    NotifyError(aDisconnectedReason);
   }
 }
 
 void
 TelephonyCall::ChangeGroup(TelephonyCallGroup* aGroup)
 {
   mGroup = aGroup;
 

--- a/dom/telephony/gonk/TelephonyService.js
+++ b/dom/telephony/gonk/TelephonyService.js
@@ -1445,20 +1445,16 @@ TelephonyService.prototype = {
     this._cdmaCallWaitingNumber = null;
   },
 
   /**
    * Disconnect calls by updating their states. Sometimes, it may cause other
    * calls being disconnected as well.
    *
    * @return Array a list of calls we need to fire callStateChange
-   *
-   * TODO: The list currently doesn't contain calls that we fire notifyError
-   * for them. However, after Bug 1147736, notifyError is replaced by
-   * callStateChanged and those calls should be included in the list.
    */
   _disconnectCalls: function(aClientId, aCalls,
                              aFailCause = RIL.GECKO_CALL_ERROR_NORMAL_CALL_CLEARING) {
     if (DEBUG) debug("_disconnectCalls: " + JSON.stringify(aCalls));
 
     // Child cannot live without parent. Let's find all the calls that need to
     // be disconnected.
     let disconnectedCalls = aCalls.slice();
@@ -1472,32 +1468,26 @@ TelephonyService.prototype = {
 
     // Store unique value in the list.
     disconnectedCalls = [...Set(disconnectedCalls)];
 
     let callsForStateChanged = [];
 
     disconnectedCalls.forEach(call => {
       call.state = nsITelephonyService.CALL_STATE_DISCONNECTED;
-      call.failCause = aFailCause;
+      call.disconnectedReason = aFailCause;
 
       if (call.parentId) {
         let parentCall = this._currentCalls[aClientId][call.parentId];
         delete parentCall.childId;
       }
 
       this._notifyCallEnded(call);
 
-      if (call.hangUpLocal || !call.failCause ||
-          call.failCause === RIL.GECKO_CALL_ERROR_NORMAL_CALL_CLEARING) {
-        callsForStateChanged.push(call);
-      } else {
-        this._notifyAllListeners("notifyError",
-                                 [aClientId, call.callIndex, call.failCause]);
-      }
+      callsForStateChanged.push(call);
 
       delete this._currentCalls[aClientId][call.callIndex];
     });
 
     return callsForStateChanged;
   },
 
   /**