diff --git a/bumble/controller.py b/bumble/controller.py
index 4ead098..53b2292 100644
--- a/bumble/controller.py
+++ b/bumble/controller.py
@@ -134,12 +134,14 @@ class Controller:
             '0000000060000000'
         )  # BR/EDR Not Supported, LE Supported (Controller)
         self.manufacturer_name = 0xFFFF
+        self.hc_data_packet_length = 27
+        self.hc_total_num_data_packets = 64
         self.hc_le_data_packet_length = 27
         self.hc_total_num_le_data_packets = 64
         self.event_mask = 0
         self.event_mask_page_2 = 0
         self.supported_commands = bytes.fromhex(
-            '2000800000c000000000e40000002822000000000000040000f7ffff7f000000'
+            '2000800000c000000000e4000000a822000000000000040000f7ffff7f000000'
             '30f0f9ff01008004000000000000000000000000000000000000000000000000'
         )
         self.le_event_mask = 0
@@ -914,6 +916,19 @@ class Controller:
         '''
         return bytes([HCI_SUCCESS]) + self.lmp_features
 
+    def on_hci_read_buffer_size_command(self, _command):
+        '''
+        See Bluetooth spec Vol 4, Part E - 7.4.5 Read Buffer Size Command
+        '''
+        return struct.pack(
+            '<BHBHH',
+            HCI_SUCCESS,
+            self.hc_data_packet_length,
+            0,
+            self.hc_total_num_data_packets,
+            0,
+        )
+
     def on_hci_read_bd_addr_command(self, _command):
         '''
         See Bluetooth spec Vol 4, Part E - 7.4.6 Read BD_ADDR Command
diff --git a/tests/device_test.py b/tests/device_test.py
index d51431f..50dd5f8 100644
--- a/tests/device_test.py
+++ b/tests/device_test.py
@@ -29,7 +29,7 @@ from bumble.core import (
     ConnectionParameters,
 )
 from bumble.device import Connection, Device
-from bumble.host import Host
+from bumble.host import AclPacketQueue, Host
 from bumble.hci import (
     HCI_ACCEPT_CONNECTION_REQUEST_COMMAND,
     HCI_COMMAND_STATUS_PENDING,
@@ -73,6 +73,13 @@ async def test_device_connect_parallel():
     d1 = Device(host=Host(None, None))
     d2 = Device(host=Host(None, None))
 
+    def _send(packet):
+        pass
+
+    d0.host.acl_packet_queue = AclPacketQueue(0, 0, _send)
+    d1.host.acl_packet_queue = AclPacketQueue(0, 0, _send)
+    d2.host.acl_packet_queue = AclPacketQueue(0, 0, _send)
+
     # enable classic
     d0.classic_enabled = True
     d1.classic_enabled = True