diff --git a/base-hw/src/core/kernel/core_interface.h b/base-hw/src/core/kernel/core_interface.h
index 3ce98dd76b..398db21440 100644
--- a/base-hw/src/core/kernel/core_interface.h
+++ b/base-hw/src/core/kernel/core_interface.h
@@ -98,6 +98,8 @@ namespace Kernel
 	 *
 	 * \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_region(addr_t const base, size_t const size)
 	{
diff --git a/base-hw/src/core/kernel/thread.cc b/base-hw/src/core/kernel/thread.cc
index e5c513e90e..33e45ba402 100644
--- a/base-hw/src/core/kernel/thread.cc
+++ b/base-hw/src/core/kernel/thread.cc
@@ -620,11 +620,7 @@ void Thread::_call_update_region()
 		PWRN("not entitled to update region");
 		return;
 	}
-	/*
-	 * Flush hardware caches
-	 *
-	 * FIXME we don't handle instruction caches by now
-	 */
+	/* flush hardware caches */
 	Processor::flush_data_cache_by_virt_region((addr_t)user_arg_1(),
 	                                           (size_t)user_arg_2());
 }