diff --git a/app/src/main/java/run/evan/modemtool/MiRilHook.java b/app/src/main/java/run/evan/modemtool/MiRilHook.java
index 87c4a9c..7d33ae1 100644
--- a/app/src/main/java/run/evan/modemtool/MiRilHook.java
+++ b/app/src/main/java/run/evan/modemtool/MiRilHook.java
@@ -15,20 +15,17 @@ import java.util.Arrays;
 public class MiRilHook extends QcRilHook {
 
 
-    private final int mHeaderSize;
 
     private static final int HOOK_HEAD_SIZE = "QOEMHOOK".length() + 8;
 
 
     public MiRilHook(Context context) {
         super(context);
-        this.mHeaderSize = "QOEMHOOK".length() + 8;
 
     }
 
     public MiRilHook(Context context, QcRilHookCallback qcRilHookCallback) {
         super(context, qcRilHookCallback);
-        this.mHeaderSize = "QOEMHOOK".length() + 8;
 
     }
 
@@ -69,8 +66,7 @@ public class MiRilHook extends QcRilHook {
 
     public org.codeaurora.telephony.utils.AsyncResult sendQcRilHookMsg(int requestId, byte[] request, int responseSize, int phoneId) {
         validateInternalState();
-        int mHeaderSize = "QOEMHOOK".length() + 8;
-        byte[] request_new = new byte[mHeaderSize + request.length];
+        byte[] request_new = new byte[HOOK_HEAD_SIZE + request.length];
         ByteBuffer reqBuffer = createBufferWithNativeByteOrder(request_new);
         addQcRilHookHeader(reqBuffer, requestId, request.length);
         reqBuffer.put(request);