diff --git a/HISTORY b/HISTORY
index 45ba1c47..400ad11c 100644
--- a/HISTORY
+++ b/HISTORY
@@ -8132,8 +8132,11 @@ Video Disk Recorder Revision History
   and also to use the correct directory with --edit (the latter reported by Marko
   Mäkelä).
 
-2014-01-07: Version 2.1.4
+2014-01-14: Version 2.1.4
 
 - Updated 'sources.conf' (thanks to Antti Hartikainen).
 - cFont::CreateFont() now returns a dummy font in case there are no fonts installed.
   This prevents a crash with the LCARS skin on a system that has no fonts.
+- Improved locking for CAM slots and made the pure functions of cCiAdapter have
+  default implementations, to fix a possible crash with CI adapters and CAM slots
+  that are implemented in a plugin.
diff --git a/ci.c b/ci.c
index e2881fed..56a4583e 100644
--- a/ci.c
+++ b/ci.c
@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: ci.c 3.4 2014/01/02 10:31:12 kls Exp $
+ * $Id: ci.c 3.5 2014/01/14 12:03:37 kls Exp $
  */
 
 #include "ci.h"
@@ -1584,6 +1584,8 @@ cCamSlot::cCamSlot(cCiAdapter *CiAdapter, bool ReceiveCaPids)
 
 cCamSlot::~cCamSlot()
 {
+  if (ciAdapter && ciAdapter->assignedDevice)
+     ciAdapter->assignedDevice->SetCamSlot(NULL);
   delete caPidReceiver;
   CamSlots.Del(this, false);
   DeleteAllConnections();
diff --git a/ci.h b/ci.h
index 11237121..e3b85912 100644
--- a/ci.h
+++ b/ci.h
@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: ci.h 3.3 2014/01/02 10:14:39 kls Exp $
+ * $Id: ci.h 3.4 2014/01/14 11:53:52 kls Exp $
  */
 
 #ifndef __CI_H
@@ -88,19 +88,19 @@ protected:
        ///< Handles the attached CAM slots in a separate thread.
        ///< The derived class must call the Start() function to
        ///< actually start CAM handling.
-  virtual int Read(uint8_t *Buffer, int MaxLength) = 0;
+  virtual int Read(uint8_t *Buffer, int MaxLength) { return 0; }
        ///< Reads one chunk of data into the given Buffer, up to MaxLength bytes.
        ///< If no data is available immediately, wait for up to CAM_READ_TIMEOUT.
        ///< Returns the number of bytes read (in case of an error it will also
        ///< return 0).
-  virtual void Write(const uint8_t *Buffer, int Length) = 0;
+  virtual void Write(const uint8_t *Buffer, int Length) {}
        ///< Writes Length bytes of the given Buffer.
-  virtual bool Reset(int Slot) = 0;
+  virtual bool Reset(int Slot) { return false; }
        ///< Resets the CAM in the given Slot.
        ///< Returns true if the operation was successful.
-  virtual eModuleStatus ModuleStatus(int Slot) = 0;
+  virtual eModuleStatus ModuleStatus(int Slot) { return msNone; }
        ///< Returns the status of the CAM in the given Slot.
-  virtual bool Assign(cDevice *Device, bool Query = false) = 0;
+  virtual bool Assign(cDevice *Device, bool Query = false) { return false; }
        ///< Assigns this adapter to the given Device, if this is possible.
        ///< If Query is 'true', the adapter only checks whether it can be
        ///< assigned to the Device, but doesn't actually assign itself to it.
diff --git a/device.c b/device.c
index 84caf4e1..b84b5a26 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 3.7 2014/01/02 10:31:58 kls Exp $
+ * $Id: device.c 3.8 2014/01/14 11:58:49 kls Exp $
  */
 
 #include "device.h"
@@ -358,6 +358,7 @@ bool cDevice::HasCi(void)
 
 void cDevice::SetCamSlot(cCamSlot *CamSlot)
 {
+  LOCK_THREAD;
   camSlot = CamSlot;
 }
 
@@ -1575,6 +1576,7 @@ void cDevice::Action(void)
      while (Running()) {
            // Read data from the DVR device:
            uchar *b = NULL;
+           LOCK_THREAD;
            if (GetTSPacket(b)) {
               if (b) {
                  int Pid = TsPid(b);
@@ -1599,7 +1601,6 @@ void cDevice::Action(void)
                        }
                     }
                  // Distribute the packet to all attached receivers:
-                 Lock();
                  for (int i = 0; i < MAXRECEIVERS; i++) {
                      if (receiver[i] && receiver[i]->WantsPid(Pid)) {
                         if (DetachReceivers) {
@@ -1612,7 +1613,6 @@ void cDevice::Action(void)
                            ChannelCamRelations.SetDecrypt(receiver[i]->ChannelID(), CamSlotNumber);
                         }
                      }
-                 Unlock();
                  }
               }
            else