diff --git a/repos/base-hw/src/include/base/internal/native_utcb.h b/repos/base-hw/src/include/base/internal/native_utcb.h
index 9ce79a8793..73ff38aba1 100644
--- a/repos/base-hw/src/include/base/internal/native_utcb.h
+++ b/repos/base-hw/src/include/base/internal/native_utcb.h
@@ -56,29 +56,29 @@ class Genode::Native_utcb
 	private:
 
 		/*
-		 * Note thats the member variables are sorted from the largest to the
-		 * smallest size to avoid padding. Otherwise, the dimensioning of
-		 * '_data' would not yield a page-sized 'Native_utcb'.
+		 * Note, the member variables are put into a header structure to ensure
+		 * the header is padded by the compiler to the next machine-word
+		 * boundary and '_data' is aligned. This also makes the dimensioning of
+		 * '_data' easy (page size - size of header).
 		 */
-
-		size_t          _cap_cnt;            /* capability counter */
-		size_t          _data_size;          /* bytes to transfer  */
-		long            _exception_code;     /* result code of RPC */
-		Kernel::capid_t _destination;        /* invoked object     */
-		Kernel::capid_t _caps[MAX_CAP_ARGS]; /* capability buffer  */
-		uint8_t         _data[get_page_size() - sizeof(_caps) -
-		                      sizeof(_cap_cnt) - sizeof(_data_size) -
-		                      sizeof(_destination) - sizeof(_exception_code)];
+		struct {
+			size_t          cap_cnt;            /* capability counter */
+			size_t          data_size;          /* bytes to transfer  */
+			long            exception_code;     /* result code of RPC */
+			Kernel::capid_t destination;        /* invoked object     */
+			Kernel::capid_t caps[MAX_CAP_ARGS]; /* capability buffer  */
+		}       _header; /* is padded to machine word boundary by the compiler */
+		uint8_t _data[get_page_size() - sizeof(_header)];
 
 	public:
 
 		Native_utcb& operator= (const Native_utcb &other)
 		{
-			_cap_cnt        = 0;
-			_data_size      = min(sizeof(_data), other._data_size);
-			_exception_code = other._exception_code;
-			_destination    = other._destination;
-			memcpy(_data, other._data, _data_size);
+			_header.cap_cnt        = 0;
+			_header.data_size      = min(sizeof(_data), other._header.data_size);
+			_header.exception_code = other._header.exception_code;
+			_header.destination    = other._header.destination;
+			memcpy(_data, other._data, _header.data_size);
 
 			return *this;
 		}
@@ -86,26 +86,26 @@ class Genode::Native_utcb
 		/**
 		 * Set the destination capability id (server object identity)
 		 */
-		void destination(Kernel::capid_t id) { _destination = id; }
+		void destination(Kernel::capid_t id) { _header.destination = id; }
 
 		/**
 		 * Return identity of invoked server object
 		 */
-		Kernel::capid_t destination() const { return _destination; }
+		Kernel::capid_t destination() const { return _header.destination; }
 
-		void exception_code(long code) { _exception_code = code; }
+		void exception_code(long code) { _header.exception_code = code; }
 
-		long exception_code() const { return _exception_code; }
+		long exception_code() const { return _header.exception_code; }
 
 		/**
 		 * Return the count of capabilities in the UTCB
 		 */
-		size_t cap_cnt() const { return _cap_cnt; }
+		size_t cap_cnt() const { return _header.cap_cnt; }
 
 		/**
 		 * Set the count of capabilities in the UTCB
 		 */
-		void cap_cnt(size_t cnt) { _cap_cnt = cnt;  }
+		void cap_cnt(size_t cnt) { _header.cap_cnt = cnt;  }
 
 		/**
 		 * Return the start address of the payload data
@@ -121,14 +121,14 @@ class Genode::Native_utcb
 		/**
 		 * Return size of message data in bytes
 		 */
-		size_t data_size() const { return _data_size; }
+		size_t data_size() const { return _header.data_size; }
 
 		/**
 		 * Define size of message data to be transferred, in bytes
 		 */
 		void data_size(size_t data_size)
 		{
-			_data_size = min(data_size, sizeof(_data));
+			_header.data_size = min(data_size, sizeof(_data));
 		}
 
 		/**
@@ -136,7 +136,7 @@ class Genode::Native_utcb
 		 */
 		Kernel::capid_t cap_get(unsigned i) const
 		{
-			return (i < MAX_CAP_ARGS) ? _caps[i] : Kernel::cap_id_invalid();
+			return (i < MAX_CAP_ARGS) ? _header.caps[i] : Kernel::cap_id_invalid();
 		}
 
 		/**
@@ -145,14 +145,14 @@ class Genode::Native_utcb
 		void cap_set(unsigned i, Kernel::capid_t cap)
 		{
 			if (i < MAX_CAP_ARGS)
-				_caps[i] = cap;
+				_header.caps[i] = cap;
 		}
 
 		/**
 		 * Set the capability id 'cap_id' at the next index
 		 */
 		void cap_add(Kernel::capid_t cap_id) {
-			if (_cap_cnt < MAX_CAP_ARGS) _caps[_cap_cnt++] = cap_id; }
+			if (_header.cap_cnt < MAX_CAP_ARGS) _header.caps[_header.cap_cnt++] = cap_id; }
 };
 
 static_assert(sizeof(Genode::Native_utcb) == Genode::get_page_size(),