diff --git a/tuhi/protocol.py b/tuhi/protocol.py
index e6f4732..1a9cc61 100644
--- a/tuhi/protocol.py
+++ b/tuhi/protocol.py
@@ -72,6 +72,7 @@ class Interactions(enum.Enum):
     START_READING = enum.auto()
     ACK_TRANSACTION = enum.auto()
     REGISTER_PRESS_BUTTON = enum.auto()
+    REGISTER_WAIT_FOR_BUTTON = enum.auto()
     REGISTER_COMPLETE = enum.auto()
 
     UNKNOWN_B1 = enum.auto()
@@ -996,29 +997,76 @@ class MsgRegisterCompleteSlate(Msg):
 class MsgRegisterPressButtonSpark(Msg):
     interaction = Interactions.REGISTER_PRESS_BUTTON
     opcode = 0xe3
-    protocol = ProtocolVersion.SLATE
+    protocol = ProtocolVersion.ANY
+    # Does not require a reply, the reply is sent in response to the
+    # physical button press.
+    requires_reply = False
 
-    # FIXME: this is almost certainly incomplete
-    def _handle_reply(self, reply):
-        if reply.opcode != 0xb3:
-            raise UnexpectedReply(reply)
+    # uuid is unused, just there so it's compatible with the slate message
+    def __init__(self, uuid=None, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.args = [0x01]
+        self.uuid = uuid
 
 
-class MsgRegisterPressButtonSlate(Msg):
+class MsgRegisterPressButtonSlateOrIntuosPro(Msg):
     interaction = Interactions.REGISTER_PRESS_BUTTON
     opcode = 0xe7
     protocol = ProtocolVersion.SLATE
+    # Does not require a reply, the reply is sent in response to the
+    # physical button press.
+    requires_reply = False
+
+    def __init__(self, uuid, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.uuid = uuid
+        self.args = [int(i) for i in binascii.unhexlify(uuid)]
+
+
+class MsgRegisterWaitForButtonSpark(Msg):
+    '''
+    .. attribute:: protocol_version
+
+    The protocol version used by this device, according to this message.
+
+    '''
+    interaction = Interactions.REGISTER_WAIT_FOR_BUTTON
+    requires_request = False
+    opcode = 0x00  # unused
+    protocol = ProtocolVersion.ANY
+
+    def __init__(self, *args, **kwargs):
+        kwargs['timeout'] = 10
+        super().__init__(*args, **kwargs)
+        self.protocol_version = ProtocolVersion.ANY
 
-    # FIXME: this is almost certainly incomplete
     def _handle_reply(self, reply):
         if reply.opcode != 0xe4:
             raise UnexpectedReply(reply)
+        self.protocol_version = ProtocolVersion.SPARK
 
 
-class MsgRegisterPressButtonIntuosPro(Msg):
-    interaction = Interactions.REGISTER_PRESS_BUTTON
-    opcode = 0xe7
+class MsgRegisterWaitForButtonSlateOrIntuosPro(Msg):
+    '''
+    .. attribute:: protocol_version
+
+    The protocol version used by this device, according to this message.
+
+    '''
+    interaction = Interactions.REGISTER_WAIT_FOR_BUTTON
+    requires_request = False
+    opcode = 0x00  # unused
+    protocol = ProtocolVersion.SLATE
+
+    def __init__(self, *args, **kwargs):
+        kwargs['timeout'] = 10
+        super().__init__(*args, **kwargs)
+        self.protocol_version = ProtocolVersion.ANY
 
     def _handle_reply(self, reply):
-        if reply.opcode != 0x53:
+        if reply.opcode == 0xe4:
+            self.protocol_version =  ProtocolVersion.SLATE
+        elif reply.opcode == 0x53:
+            self.protocol_version =  ProtocolVersion.INTUOS_PRO
+        else:
             raise UnexpectedReply(reply)
diff --git a/tuhi/wacom.py b/tuhi/wacom.py
index 65153b7..2b70467 100644
--- a/tuhi/wacom.py
+++ b/tuhi/wacom.py
@@ -564,41 +564,41 @@ class WacomRegisterHelper(WacomProtocolLowLevelComm):
 
     def register_device(self, uuid):
         protocol = Protocol.UNKNOWN
-        args = [int(i) for i in binascii.unhexlify(uuid)]
 
         if self.is_spark(self.device):
+            self.p = tuhi.protocol.Protocol(ProtocolVersion.SPARK, self.nordic_data_exchange)
             # The spark replies with b3 01 01 when in pairing mode
             # Usually that triggers a WacomWrongModeException but here it's
             # expected
             try:
-                self.send_nordic_command_sync(command=0xe6, arguments=args)
-            except WacomWrongModeException:
+                self.p.execute(Interactions.CONNECT, uuid)
+            except tuhi.protocol.DeviceError:
                 # this is expected
                 pass
 
             # The "press button now command" on the spark
-            self.send_nordic_command(command=0xe3,
-                                     arguments=[0x01])
-            protocol = Protocol.SPARK
+            self.p.execute(Interactions.REGISTER_PRESS_BUTTON)
         else:
-            # Slate requires a button press in response to e7 directly
-            self.send_nordic_command(command=0xe7, arguments=args)
+            # Default to Slate for now, it will handle the IntuosPro too
+            self.p = tuhi.protocol.Protocol(ProtocolVersion.SLATE, self.nordic_data_exchange)
+            self.p.execute(Interactions.REGISTER_PRESS_BUTTON, uuid)
 
         logger.info('Press the button now to confirm')
         self.emit('button-press-required')
 
         # Wait for the button confirmation event, or any error
-        data = self.wait_nordic_data([0xe4, 0xb3, 0x53], 10)
+        protocol_version = self.p.execute(Interactions.REGISTER_WAIT_FOR_BUTTON).protocol_version
 
-        if protocol == Protocol.UNKNOWN:
-            if data.opcode == 0xe4:
-                protocol = Protocol.SLATE
-            elif data.opcode == 0x53:
-                protocol = Protocol.INTUOS_PRO
-            else:
-                raise WacomException(f'unexpected opcode to register reply: {data.opcode:02x}')
+        if protocol_version == ProtocolVersion.ANY:
+                raise WacomException(f'Unknown protocol version: {protocol_version}')
 
-        return protocol
+        pvmap = {
+            ProtocolVersion.SPARK: Protocol.SPARK,
+            ProtocolVersion.SLATE: Protocol.SLATE,
+            ProtocolVersion.INTUOS_PRO: Protocol.INTUOS_PRO,
+        }
+
+        return pvmap[protocol_version]
 
 
 class WacomProtocolBase(WacomProtocolLowLevelComm):