diff --git a/libs/binder/AppOpsManager.cpp b/libs/binder/AppOpsManager.cpp
index 61b4f7d..c562c30 100644
--- a/libs/binder/AppOpsManager.cpp
+++ b/libs/binder/AppOpsManager.cpp
@@ -44,7 +44,7 @@
     int64_t startTime = 0;
     mLock.lock();
     sp<IAppOpsService> service = mService;
-    while (service == NULL || !service->asBinder()->isBinderAlive()) {
+    while (service == NULL || !IInterface::asBinder(service)->isBinderAlive()) {
         sp<IBinder> binder = defaultServiceManager()->checkService(_appops);
         if (binder == NULL) {
             // Wait for the app ops service to come back...
diff --git a/libs/binder/IAppOpsService.cpp b/libs/binder/IAppOpsService.cpp
index f58a352..86abdc0 100644
--- a/libs/binder/IAppOpsService.cpp
+++ b/libs/binder/IAppOpsService.cpp
@@ -91,14 +91,14 @@
         data.writeInterfaceToken(IAppOpsService::getInterfaceDescriptor());
         data.writeInt32(op);
         data.writeString16(packageName);
-        data.writeStrongBinder(callback->asBinder());
+        data.writeStrongBinder(IInterface::asBinder(callback));
         remote()->transact(START_WATCHING_MODE_TRANSACTION, data, &reply);
     }
 
     virtual void stopWatchingMode(const sp<IAppOpsCallback>& callback) {
         Parcel data, reply;
         data.writeInterfaceToken(IAppOpsService::getInterfaceDescriptor());
-        data.writeStrongBinder(callback->asBinder());
+        data.writeStrongBinder(IInterface::asBinder(callback));
         remote()->transact(STOP_WATCHING_MODE_TRANSACTION, data, &reply);
     }
 
diff --git a/libs/binder/IInterface.cpp b/libs/binder/IInterface.cpp
index 99a9ffe..8c60dc4 100644
--- a/libs/binder/IInterface.cpp
+++ b/libs/binder/IInterface.cpp
@@ -27,14 +27,18 @@
 IInterface::~IInterface() {
 }
 
-sp<IBinder> IInterface::asBinder()
+// static
+sp<IBinder> IInterface::asBinder(const IInterface* iface)
 {
-    return onAsBinder();
+    if (iface == NULL) return NULL;
+    return const_cast<IInterface*>(iface)->onAsBinder();
 }
 
-sp<const IBinder> IInterface::asBinder() const
+// static
+sp<IBinder> IInterface::asBinder(const sp<IInterface>& iface)
 {
-    return const_cast<IInterface*>(this)->onAsBinder();
+    if (iface == NULL) return NULL;
+    return iface->onAsBinder();
 }
 
 // ---------------------------------------------------------------------------
diff --git a/libs/binder/IMemory.cpp b/libs/binder/IMemory.cpp
index d8ed995..e9891a8 100644
--- a/libs/binder/IMemory.cpp
+++ b/libs/binder/IMemory.cpp
@@ -216,7 +216,7 @@
             CHECK_INTERFACE(IMemory, data, reply);
             ssize_t offset;
             size_t size;
-            reply->writeStrongBinder( getMemory(&offset, &size)->asBinder() );
+            reply->writeStrongBinder( IInterface::asBinder(getMemory(&offset, &size)) );
             reply->writeInt32(offset);
             reply->writeInt32(size);
             return NO_ERROR;
@@ -241,7 +241,7 @@
         if (mRealHeap) {
             // by construction we're the last one
             if (mBase != MAP_FAILED) {
-                sp<IBinder> binder = const_cast<BpMemoryHeap*>(this)->asBinder();
+                sp<IBinder> binder = IInterface::asBinder(this);
 
                 if (VERBOSE) {
                     ALOGD("UNMAPPING binder=%p, heap=%p, size=%zu, fd=%d",
@@ -253,7 +253,7 @@
             }
         } else {
             // remove from list only if it was mapped before
-            sp<IBinder> binder = const_cast<BpMemoryHeap*>(this)->asBinder();
+            sp<IBinder> binder = IInterface::asBinder(this);
             free_heap(binder);
         }
     }
@@ -262,7 +262,7 @@
 void BpMemoryHeap::assertMapped() const
 {
     if (mHeapId == -1) {
-        sp<IBinder> binder(const_cast<BpMemoryHeap*>(this)->asBinder());
+        sp<IBinder> binder(IInterface::asBinder(const_cast<BpMemoryHeap*>(this)));
         sp<BpMemoryHeap> heap(static_cast<BpMemoryHeap*>(find_heap(binder).get()));
         heap->assertReallyMapped();
         if (heap->mBase != MAP_FAILED) {
@@ -297,7 +297,8 @@
         uint32_t offset = reply.readInt32();
 
         ALOGE_IF(err, "binder=%p transaction failed fd=%d, size=%zd, err=%d (%s)",
-                asBinder().get(), parcel_fd, size, err, strerror(-err));
+                IInterface::asBinder(this).get(),
+                parcel_fd, size, err, strerror(-err));
 
         int fd = dup( parcel_fd );
         ALOGE_IF(fd==-1, "cannot dup fd=%d, size=%zd, err=%d (%s)",
@@ -314,7 +315,7 @@
             mBase = mmap(0, size, access, MAP_SHARED, fd, offset);
             if (mBase == MAP_FAILED) {
                 ALOGE("cannot map BpMemoryHeap (binder=%p), size=%zd, fd=%d (%s)",
-                        asBinder().get(), size, fd, strerror(errno));
+                        IInterface::asBinder(this).get(), size, fd, strerror(errno));
                 close(fd);
             } else {
                 mSize = size;
diff --git a/libs/binder/IServiceManager.cpp b/libs/binder/IServiceManager.cpp
index 7b1b0e7..3c716df 100644
--- a/libs/binder/IServiceManager.cpp
+++ b/libs/binder/IServiceManager.cpp
@@ -87,7 +87,7 @@
             }
             
             // Is this a permission failure, or did the controller go away?
-            if (pc->asBinder()->isBinderAlive()) {
+            if (IInterface::asBinder(pc)->isBinderAlive()) {
                 ALOGW("Permission failure: %s from uid=%d pid=%d",
                         String8(permission).string(), uid, pid);
                 return false;