diff --git a/stub-ext/stubext.h b/stub-ext/stubext.h
index 071070ca047dc6a0a5282afd337d937932889dbe..51b930f486c7b9c3bd67ec46898d08382d1cbc6d 100644
--- a/stub-ext/stubext.h
+++ b/stub-ext/stubext.h
@@ -44,7 +44,7 @@ public:
     template<typename T, class Lamda>
     bool set_lamda(T addr, Lamda lamda)
     {
-        char *fn = reinterpret_cast<char*>(addrof(addr));
+        unsigned char *fn = addrof(addr);
         if (m_result.find(fn) != m_result.end()) {
             assert(m_result.find(fn) == m_result.end());
             return false;
@@ -52,20 +52,16 @@ public:
 
         Wrapper *wrapper = nullptr;
         auto addr_stub = depictShadow(&wrapper,addr,lamda);
-        if (set(addr, addr_stub)) {
-            m_wrappers.insert(std::make_pair(fn, wrapper));
-            return true;
-        } else {
-            freeWrapper(wrapper);
-        }
-        return false;
+        set(addr, addr_stub);
+        m_wrappers.insert(std::make_pair(fn, wrapper));
+        return true;
     }
 
     template<typename T>
     void reset(T addr)
     {
         Stub::reset(addr);
-        char *fn = reinterpret_cast<char*>(addrof(addr));
+        unsigned char *fn = addrof(addr);
         auto iter = m_wrappers.find(fn);
         if (iter != m_wrappers.end()) {
             freeWrapper(iter->second);
@@ -80,7 +76,7 @@ public:
         }
     }
 protected:
-    std::map<char*, Wrapper*> m_wrappers;
+    std::map<unsigned char*, Wrapper*> m_wrappers;
 };
 
 }