diff --git a/jni/android_hardware_fm.cpp b/jni/android_hardware_fm.cpp
index 76490ee..6809a27 100644
--- a/jni/android_hardware_fm.cpp
+++ b/jni/android_hardware_fm.cpp
@@ -486,6 +486,7 @@
             return;
         }
         vm->DetachCurrentThread();
+        mCallbackEnv = NULL;
     }
 }