diff --git a/base-hw/include/kernel/interface.h b/base-hw/include/kernel/interface.h
index 82b5be63e..23cb44e15 100644
--- a/base-hw/include/kernel/interface.h
+++ b/base-hw/include/kernel/interface.h
@@ -47,6 +47,7 @@ namespace Kernel
 	constexpr Call_arg call_id_signal_pending()       { return 9; }
 	constexpr Call_arg call_id_ack_signal()           { return 10; }
 	constexpr Call_arg call_id_print_char()           { return 11; }
+	constexpr Call_arg call_id_update_data_region()   { return 12; }
 
 
 	/*****************************************************************
@@ -120,6 +121,16 @@ namespace Kernel
 		call(call_id_yield_thread(), thread_id);
 	}
 
+	/**
+	 * Globally apply writes to a data region in the current domain
+	 *
+	 * \param base  base of the region within the current domain
+	 * \param size  size of the region
+	 */
+	inline void update_data_region(addr_t const base, size_t const size)
+	{
+		call(call_id_update_data_region(), (Call_arg)base, (Call_arg)size);
+	}
 
 	/**
 	 * Send request message and await receipt of corresponding reply message
diff --git a/base-hw/src/core/kernel/core_interface.h b/base-hw/src/core/kernel/core_interface.h
index 906e47efa..89823b0af 100644
--- a/base-hw/src/core/kernel/core_interface.h
+++ b/base-hw/src/core/kernel/core_interface.h
@@ -31,14 +31,13 @@ namespace Kernel
 	/**
 	 * Kernel names of the kernel calls
 	 */
-	constexpr Call_arg call_id_new_thread()          { return 12; }
-	constexpr Call_arg call_id_bin_thread()          { return 13; }
-	constexpr Call_arg call_id_start_thread()        { return 14; }
-	constexpr Call_arg call_id_resume_thread()       { return 15; }
-	constexpr Call_arg call_id_access_thread_regs()  { return 16; }
-	constexpr Call_arg call_id_route_thread_event()  { return 17; }
-	constexpr Call_arg call_id_update_pd()           { return 18; }
-	constexpr Call_arg call_id_update_data_region()  { return 19; }
+	constexpr Call_arg call_id_new_thread()          { return 13; }
+	constexpr Call_arg call_id_bin_thread()          { return 14; }
+	constexpr Call_arg call_id_start_thread()        { return 15; }
+	constexpr Call_arg call_id_resume_thread()       { return 16; }
+	constexpr Call_arg call_id_access_thread_regs()  { return 17; }
+	constexpr Call_arg call_id_route_thread_event()  { return 18; }
+	constexpr Call_arg call_id_update_pd()           { return 19; }
 	constexpr Call_arg call_id_new_pd()              { return 20; }
 	constexpr Call_arg call_id_bin_pd()              { return 21; }
 	constexpr Call_arg call_id_new_signal_receiver() { return 22; }
@@ -94,20 +93,6 @@ namespace Kernel
 	}
 
 
-	/**
-	 * Write-through the cached contents of a region in the current domain
-	 *
-	 * \param base  base of the region within the current domain
-	 * \param size  size of the region
-	 *
-	 * Does apply only to data caches.
-	 */
-	inline void update_data_region(addr_t const base, size_t const size)
-	{
-		call(call_id_update_data_region(), (Call_arg)base, (Call_arg)size);
-	}
-
-
 	/**
 	 * Create a thread
 	 *
diff --git a/base-hw/src/core/kernel/thread.cc b/base-hw/src/core/kernel/thread.cc
index 065685cd0..36b276e47 100644
--- a/base-hw/src/core/kernel/thread.cc
+++ b/base-hw/src/core/kernel/thread.cc
@@ -543,9 +543,9 @@ void Thread::_call_update_pd()
 
 void Thread::_call_update_data_region()
 {
-	/* flush hardware caches */
-	Processor::flush_data_caches_by_virt_region((addr_t)user_arg_1(),
-	                                            (size_t)user_arg_2());
+	auto base = (addr_t)user_arg_1();
+	auto const size = (size_t)user_arg_2();
+	Processor::flush_data_caches_by_virt_region(base, size);
 }
 
 
@@ -855,6 +855,7 @@ void Thread::_call()
 	/* switch over unrestricted kernel calls */
 	unsigned const call_id = user_arg_0();
 	switch (call_id) {
+	case call_id_update_data_region():   _call_update_data_region(); return;
 	case call_id_pause_current_thread(): _call_pause_current_thread(); return;
 	case call_id_resume_local_thread():  _call_resume_local_thread(); return;
 	case call_id_yield_thread():         _call_yield_thread(); return;
@@ -884,7 +885,6 @@ void Thread::_call()
 	case call_id_access_thread_regs():  _call_access_thread_regs(); return;
 	case call_id_route_thread_event():  _call_route_thread_event(); return;
 	case call_id_update_pd():           _call_update_pd(); return;
-	case call_id_update_data_region():  _call_update_data_region(); return;
 	case call_id_new_pd():              _call_new_pd(); return;
 	case call_id_bin_pd():              _call_bin_pd(); return;
 	case call_id_new_signal_receiver(): _call_new_signal_receiver(); return;