receiver: use Bolt unique ID as serial number

lib/logitech_receiver/hidpp10.py

@@ -123,6 +123,7 @@ REGISTERS = _NamedInts(
     receiver_info=0x2B5,
     bolt_device_discovery=0xC0,
     bolt_pairing=0x2C1,
+    bolt_uniqueId=0x02FB,
 
     # only apply to devices
     mouse_button_flags=0x01,

lib/logitech_receiver/receiver.py

@@ -63,7 +63,10 @@ class Receiver:
 
         # read the serial immediately, so we can find out max_devices
         if self.receiver_kind == 'bolt':
-            serial_reply = None
+            serial_reply = self.read_register(_R.bolt_uniqueId)
+            self.serial = _strhex(serial_reply)
+            self.max_devices = product_info.get('max_devices', 1)
+            self.may_unpair = product_info.get('may_unpair', False)
         else:
             serial_reply = self.read_register(_R.receiver_info, _IR.receiver_information)
             if serial_reply: