diff --git a/src/calibre/ebooks/metadata/book/json_codec.py b/src/calibre/ebooks/metadata/book/json_codec.py
index 8e2dc64383..cc9b6f252d 100644
--- a/src/calibre/ebooks/metadata/book/json_codec.py
+++ b/src/calibre/ebooks/metadata/book/json_codec.py
@@ -160,7 +160,6 @@ class JsonCodec(object):
         js = []
         try:
             js = json.load(file_, encoding='utf-8')
-            self.raw_to_booklist(js, booklist, book_class, prefix)
             for item in js:
                 booklist.append(self.raw_to_book(item, book_class, prefix))
         except:
diff --git a/src/calibre/gui2/device.py b/src/calibre/gui2/device.py
index da2c45fd9c..17f1e47853 100644
--- a/src/calibre/gui2/device.py
+++ b/src/calibre/gui2/device.py
@@ -967,6 +967,11 @@ class DeviceMixin(object): # {{{
 
         fmt = None
         if specific:
+            if (not self.device_connected or not self.device_manager or
+                    self.device_manager.device is None):
+                error_dialog(self, _('No device'),
+                        _('No device connected'), show=True)
+                return
             formats = []
             aval_out_formats = available_output_formats()
             format_count = {}
diff --git a/src/calibre/library/server/base.py b/src/calibre/library/server/base.py
index a61d2dcc3e..d912165734 100644
--- a/src/calibre/library/server/base.py
+++ b/src/calibre/library/server/base.py
@@ -78,13 +78,18 @@ class BonJour(SimplePlugin): # {{{
         SimplePlugin.__init__(self, engine)
         self.port = port
         self.prefix = prefix
+        self.mdns_services = [
+            ('Books in calibre', '_stanza._tcp', self.port,
+                {'path':self.prefix+'/stanza'}),
+            ('Books in calibre', '_calibre._tcp', self.port,
+                {'path':self.prefix+'/opds'}),
+        ]
+
 
     def start(self):
         try:
-            publish_zeroconf('Books in calibre', '_stanza._tcp',
-                            self.port, {'path':self.prefix+'/stanza'})
-            publish_zeroconf('Books in calibre', '_calibre._tcp',
-                    self.port, {'path':self.prefix+'/opds'})
+            for s in self.mdns_services:
+                publish_zeroconf(*s)
         except:
             import traceback
             cherrypy.log.error('Failed to start BonJour:')
@@ -94,10 +99,8 @@ class BonJour(SimplePlugin): # {{{
 
     def stop(self):
         try:
-            unpublish_zeroconf('Books in calibre', '_stanza._tcp',
-                            self.port, {'path':self.prefix+'/stanza'})
-            unpublish_zeroconf('Books in calibre', '_calibre._tcp',
-                    self.port, {'path':self.prefix+'/opds'})
+            for s in self.mdns_services:
+                unpublish_zeroconf(*s)
         except:
             import traceback
             cherrypy.log.error('Failed to stop BonJour:')
diff --git a/src/calibre/utils/mdns.py b/src/calibre/utils/mdns.py
index 42e846577e..9232aab994 100644
--- a/src/calibre/utils/mdns.py
+++ b/src/calibre/utils/mdns.py
@@ -47,6 +47,25 @@ def start_server():
 
     return _server
 
+def create_service(desc, type, port, properties, add_hostname):
+    port = int(port)
+    try:
+        hostname = socket.gethostname().partition('.')[0]
+    except:
+        hostname = 'Unknown'
+
+    if add_hostname:
+        desc += ' (on %s)'%hostname
+    local_ip = get_external_ip()
+    type = type+'.local.'
+    from calibre.utils.Zeroconf import ServiceInfo
+    return ServiceInfo(type, desc+'.'+type,
+                          address=socket.inet_aton(local_ip),
+                          port=port,
+                          properties=properties,
+                          server=hostname+'.local.')
+
+
 def publish(desc, type, port, properties=None, add_hostname=True):
     '''
     Publish a service.
@@ -57,23 +76,8 @@ def publish(desc, type, port, properties=None, add_hostname=True):
     :param properties: An optional dictionary whose keys and values will be put
                        into the TXT record.
     '''
-    port = int(port)
     server = start_server()
-    try:
-        hostname = socket.gethostname().partition('.')[0]
-    except:
-        hostname = 'Unknown'
-
-    if add_hostname:
-        desc += ' (on %s)'%hostname
-    local_ip = get_external_ip()
-    type = type+'.local.'
-    from calibre.utils.Zeroconf import ServiceInfo
-    service = ServiceInfo(type, desc+'.'+type,
-                          address=socket.inet_aton(local_ip),
-                          port=port,
-                          properties=properties,
-                          server=hostname+'.local.')
+    service = create_service(desc, type, port, properties, add_hostname)
     server.registerService(service)
 
 def unpublish(desc, type, port, properties=None, add_hostname=True):
@@ -82,23 +86,8 @@ def unpublish(desc, type, port, properties=None, add_hostname=True):
 
     The parameters must be the same as used in the corresponding call to publish
     '''
-    port = int(port)
     server = start_server()
-    try:
-        hostname = socket.gethostname().partition('.')[0]
-    except:
-        hostname = 'Unknown'
-
-    if add_hostname:
-        desc += ' (on %s)'%hostname
-    local_ip = get_external_ip()
-    type = type+'.local.'
-    from calibre.utils.Zeroconf import ServiceInfo
-    service = ServiceInfo(type, desc+'.'+type,
-                          address=socket.inet_aton(local_ip),
-                          port=port,
-                          properties=properties,
-                          server=hostname+'.local.')
+    service = create_service(desc, type, port, properties, add_hostname)
     server.unregisterService(service)
     if server.countRegisteredServices() == 0:
         stop_server()