Index: kernel/generic/include/ipc/ipc.h
===================================================================
--- kernel/generic/include/ipc/ipc.h	(revision b9cb911d917500f6e3b651f8bed352330f8a9839)
+++ kernel/generic/include/ipc/ipc.h	(revision 205832be3aac366938f4e110d02825acf0142693)
@@ -77,7 +77,4 @@
 	waitq_t wq;
 	
-	/** Linkage for the list of task's synchronous answerboxes. */
-	link_t sync_box_link;
-	
 	/** Phones connected to this answerbox. */
 	list_t connected_phones;
@@ -116,10 +113,4 @@
 	struct task *sender;
 	
-	/*
-	 * The caller box is different from sender->answerbox
-	 * for synchronous calls.
-	 */
-	answerbox_t *callerbox;
-	
 	/** Private data to internal IPC. */
 	sysarg_t priv;
@@ -147,5 +138,4 @@
 
 extern int ipc_call(phone_t *, call_t *);
-extern int ipc_call_sync(phone_t *, call_t *);
 extern call_t *ipc_wait_for_call(answerbox_t *, uint32_t, unsigned int);
 extern int ipc_forward(call_t *, phone_t *, answerbox_t *, unsigned int);
Index: kernel/generic/include/ipc/sysipc.h
===================================================================
--- kernel/generic/include/ipc/sysipc.h	(revision b9cb911d917500f6e3b651f8bed352330f8a9839)
+++ kernel/generic/include/ipc/sysipc.h	(revision 205832be3aac366938f4e110d02825acf0142693)
@@ -40,7 +40,4 @@
 #include <typedefs.h>
 
-extern sysarg_t sys_ipc_call_sync_fast(sysarg_t, sysarg_t, sysarg_t,
-    sysarg_t, sysarg_t, ipc_data_t *);
-extern sysarg_t sys_ipc_call_sync_slow(sysarg_t, ipc_data_t *, ipc_data_t *);
 extern sysarg_t sys_ipc_call_async_fast(sysarg_t, sysarg_t, sysarg_t,
     sysarg_t, sysarg_t, sysarg_t);
Index: kernel/generic/include/proc/task.h
===================================================================
--- kernel/generic/include/proc/task.h	(revision b9cb911d917500f6e3b651f8bed352330f8a9839)
+++ kernel/generic/include/proc/task.h	(revision 205832be3aac366938f4e110d02825acf0142693)
@@ -98,5 +98,4 @@
 	phone_t phones[IPC_MAX_PHONES];
 	stats_ipc_t ipc_info;   /**< IPC statistics */
-	list_t sync_boxes;      /**< List of synchronous answerboxes. */
 	event_t events[EVENT_TASK_END - EVENT_END];