diff --git a/cdcftdi.cpp b/cdcftdi.cpp
index 13ca683f..8f07b358 100644
--- a/cdcftdi.cpp
+++ b/cdcftdi.cpp
@@ -246,7 +246,7 @@ uint8_t FTDI::Release() {
         bNumEP = 1;
         qNextPollTime = 0;
         bPollEnable = false;
-        return 0;
+        return pAsync->OnRelease(this);
 }
 
 uint8_t FTDI::Poll() {
diff --git a/cdcftdi.h b/cdcftdi.h
index 692ec6b0..fbb7396d 100644
--- a/cdcftdi.h
+++ b/cdcftdi.h
@@ -79,6 +79,7 @@ class FTDI;
 class FTDIAsyncOper {
 public:
         virtual uint8_t OnInit(FTDI *pftdi) = 0;
+        virtual uint8_t OnRelease(FTDI *pftdi) = 0;
 };