diff --git a/HISTORY b/HISTORY
index 1f49b1a1..e1a11ab4 100644
--- a/HISTORY
+++ b/HISTORY
@@ -7191,7 +7191,7 @@ Video Disk Recorder Revision History
   turn on adding the source character to channel names whenever they are displayed
   (suggested by Ludi Kaleni).
 
-2012-09-01: Version 1.7.30
+2012-09-02: Version 1.7.30
 
 - Fixed sorting recordings in the top level video directory.
 - Fixed handling control characters in SI data in case of UTF-8 encoded strings
@@ -7206,6 +7206,9 @@ Video Disk Recorder Revision History
 - Fixed detecting transfer mode on full featured DVB cards (thanks to Stefan Huelswitt
   for reporting a problem with updating CA descriptors in such cases).
 - Fixed a race condition when zapping in transfer mode (reported by Reinhard Nissl).
+  This involves a slight change in the semantics of the cReceiver::Activate() function,
+  which is now called with 'false' *after* the receiver has been detached from the
+  device.
 - The new function cDevice::ReadFilter() can be used by devices to implement their
   own way of retrieving section filter data (thanks to Deti Fliegl).
 - The new function cDevice::HasInternalCam() can be implemented by devices that
diff --git a/device.c b/device.c
index a5a0ec78..6518e820 100644
--- a/device.c
+++ b/device.c
@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: device.c 2.66 2012/08/31 11:02:24 kls Exp $
+ * $Id: device.c 2.67 2012/09/02 09:26:36 kls Exp $
  */
 
 #include "device.h"
@@ -1676,10 +1676,10 @@ void cDevice::Detach(cReceiver *Receiver)
   for (int i = 0; i < MAXRECEIVERS; i++) {
       if (receiver[i] == Receiver) {
          Lock();
-         Receiver->Activate(false);
          receiver[i] = NULL;
          Receiver->device = NULL;
          Unlock();
+         Receiver->Activate(false);
          for (int n = 0; n < Receiver->numPids; n++)
              DelPid(Receiver->pids[n]);
          }
diff --git a/receiver.h b/receiver.h
index eb2f32a7..775dabdf 100644
--- a/receiver.h
+++ b/receiver.h
@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: receiver.h 2.8 2012/06/02 13:20:44 kls Exp $
+ * $Id: receiver.h 2.9 2012/09/02 09:27:20 kls Exp $
  */
 
 #ifndef __RECEIVER_H
@@ -27,7 +27,7 @@ protected:
   void Detach(void);
   virtual void Activate(bool On) {}
                ///< This function is called just before the cReceiver gets attached to
-               ///< (On == true) or detached from (On == false) a cDevice. It can be used
+               ///< (On == true) and right after it gets detached from (On == false) a cDevice. It can be used
                ///< to do things like starting/stopping a thread.
                ///< It is guaranteed that Receive() will not be called before Activate(true).
   virtual void Receive(uchar *Data, int Length) = 0;