diff --git a/app/receiver.py b/app/receiver.py
index 9c928ea2..7ec7625f 100644
--- a/app/receiver.py
+++ b/app/receiver.py
@@ -105,13 +105,11 @@ class _FeaturesArray(object):
 class DeviceInfo(_api.PairedDevice):
 	"""A device attached to the receiver.
 	"""
-	def __init__(self, listener, number, serial_prefix, status=STATUS.UNKNOWN):
+	def __init__(self, listener, number, status=STATUS.UNKNOWN):
 		super(DeviceInfo, self).__init__(listener.handle, number)
 
 		self.LOG = _Logger("Device[%d]" % number)
 		self._listener = listener
-		self._pair_code = _pack('!B', 0x40 + number - 1)
-		self._serial_prefix = _base._hex(serial_prefix)
 		self._serial = None
 		self._codename = None
 
@@ -182,18 +180,17 @@ class DeviceInfo(_api.PairedDevice):
 	@property
 	def serial(self):
 		if self._serial is None:
-			# dodgy
-			b = bytearray(self._pair_code)
-			b[0] -= 0x10
-			serial = _base.request(self.handle, 0xFF, b'\x83\xB5', bytes(b))
-			if serial:
-				self._serial = self._serial_prefix + '-' + _base._hex(serial[1:5])
-		return self._serial or self._serial_prefix + '-?'
+			prefix = _base.request(self.handle, 0xFF, b'\x83\xB5', 0x20 + self.number - 1)
+			prefix = (_base._hex(prefix[3:5]) + '-') if prefix else ''
+			serial = _base.request(self.handle, 0xFF, b'\x83\xB5', 0x30 + self.number - 1)
+			serial = _base._hex(serial[1:5]) if serial else '?'
+			self._serial = prefix + serial
+		return self._serial or '?'
 
 	@property
 	def codename(self):
 		if self._codename is None:
-			codename = _base.request(self.handle, 0xFF, b'\x83\xB5', self._pair_code)
+			codename = _base.request(self.handle, 0xFF, b'\x83\xB5', 0x40 + self.number - 1)
 			if codename:
 				self._codename = codename[2:].rstrip(b'\x00').decode('ascii')
 		return self._codename or '?'
@@ -345,8 +342,7 @@ class ReceiverListener(_EventsListener):
 
 		status = self._device_status_from(event)
 		if status is not None:
-			serial_prefix = event.data[-1:] + event.data[-2:-1]
-			dev = DeviceInfo(self, event.devnumber, serial_prefix, status)
+			dev = DeviceInfo(self, event.devnumber, status)
 			self.LOG.info("new device %s", dev)
 			self.status_changed(dev, True)
 			return dev