diff --git a/gns3server/modules/base_manager.py b/gns3server/modules/base_manager.py
index 5c5d9de4..f4186b2b 100644
--- a/gns3server/modules/base_manager.py
+++ b/gns3server/modules/base_manager.py
@@ -95,6 +95,7 @@ class BaseManager:
         return self._config
 
     @classmethod
+    @asyncio.coroutine
     def unload(cls):
 
         # TODO: close explicitly all the VMs here?
diff --git a/gns3server/modules/virtualbox/virtualbox_vm.py b/gns3server/modules/virtualbox/virtualbox_vm.py
index 47c5d8e3..2bbe91c0 100644
--- a/gns3server/modules/virtualbox/virtualbox_vm.py
+++ b/gns3server/modules/virtualbox/virtualbox_vm.py
@@ -33,7 +33,7 @@ import shutil
 from pkg_resources import parse_version
 from .virtualbox_error import VirtualBoxError
 from ..adapters.ethernet_adapter import EthernetAdapter
-from .telnet_server import TelnetServer
+from .telnet_server import TelnetServer  # port TelnetServer to asyncio
 from ..base_vm import BaseVM
 
 if sys.platform.startswith('win'):
@@ -70,22 +70,18 @@ class VirtualBoxVM(BaseVM):
         self._adapter_start_index = 0
         self._adapter_type = "Intel PRO/1000 MT Desktop (82540EM)"
 
-        # TODO: finish adapters support
-        # self.adapters = 2  # creates 2 adapters by default
-
     def __json__(self):
 
-        # TODO: send adapters info
-        #  "adapter_start_index": self._adapter_start_index,
-        #  "adapter_type": "Intel PRO/1000 MT Desktop (82540EM)",
-
         return {"name": self.name,
                 "uuid": self.uuid,
                 "project_uuid": self.project.uuid,
                 "vmname": self.vmname,
                 "linked_clone": self.linked_clone,
                 "headless": self.headless,
-                "enable_remote_console": self.enable_remote_console}
+                "enable_remote_console": self.enable_remote_console,
+                "adapters": self.adapters,
+                "adapter_type": self.adapter_type,
+                "adapter_start_index": self.adapter_start_index}
 
     @asyncio.coroutine
     def _execute(self, subcommand, args, timeout=60):
@@ -204,6 +200,9 @@ class VirtualBoxVM(BaseVM):
             else:
                 yield from self._create_linked_clone()
 
+        # set 2 adapters by default
+        # yield from self.set_adapters(2)
+
     @asyncio.coroutine
     def start(self):
         """
@@ -526,8 +525,8 @@ class VirtualBoxVM(BaseVM):
 
         return len(self._ethernet_adapters)
 
-    @adapters.setter
-    def adapters(self, adapters):
+    @asyncio.coroutine
+    def set_adapters(self, adapters):
         """
         Sets the number of Ethernet adapters for this VirtualBox VM instance.
 
@@ -535,7 +534,7 @@ class VirtualBoxVM(BaseVM):
         """
 
         # check for the maximum adapters supported by the VM
-        self._maximum_adapters = self._get_maximum_supported_adapters()
+        self._maximum_adapters = yield from self._get_maximum_supported_adapters()
         if len(self._ethernet_adapters) > self._maximum_adapters:
             raise VirtualBoxError("Number of adapters above the maximum supported of {}".format(self._maximum_adapters))
 
diff --git a/gns3server/schemas/virtualbox.py b/gns3server/schemas/virtualbox.py
index 760516f6..3beb7262 100644
--- a/gns3server/schemas/virtualbox.py
+++ b/gns3server/schemas/virtualbox.py
@@ -99,6 +99,23 @@ VBOX_OBJECT_SCHEMA = {
             "description": "headless mode",
             "type": "boolean"
         },
+        "adapters": {
+            "description": "number of adapters",
+            "type": "integer",
+            "minimum": 0,
+            "maximum": 36,  # maximum given by the ICH9 chipset in VirtualBox
+        },
+        "adapter_start_index": {
+            "description": "adapter index from which to start using adapters",
+            "type": "integer",
+            "minimum": 0,
+            "maximum": 35,  # maximum given by the ICH9 chipset in VirtualBox
+        },
+        "adapter_type": {
+            "description": "VirtualBox adapter type",
+            "type": "string",
+            "minLength": 1,
+        },
         "console": {
             "description": "console TCP port",
             "minimum": 1,