diff --git a/lib/cmdlib.py b/lib/cmdlib.py
index 0904e7f9f9d33249591e728a2b1a3b6ac24c554c..bccb2d4fd65d1c0b5f8ce5a0dd97a9f606bffe0f 100644
--- a/lib/cmdlib.py
+++ b/lib/cmdlib.py
@@ -12821,11 +12821,12 @@ class LUInstanceSetParams(LogicalUnit):
 
     if self.op.hotplug and disk.pci:
       self.LogInfo("Trying to hotplug device.")
-      disk_ok, device_info = _AssembleInstanceDisks(self, self.instance,
+      _, device_info = _AssembleInstanceDisks(self, self.instance,
                                                     [disk], check=False)
       _, _, dev_path = device_info[0]
-      result = self.rpc.call_hot_add_disk(self.instance.primary_node,
-                                          self.instance, disk, dev_path, idx)
+      #TODO: handle result
+      self.rpc.call_hot_add_disk(self.instance.primary_node,
+                                 self.instance, disk, dev_path, idx)
     return (disk, [
       ("disk/%d" % idx, "add:size=%s,mode=%s" % (disk.size, disk.mode)),
       ])
@@ -12890,8 +12891,8 @@ class LUInstanceSetParams(LogicalUnit):
       if pci is not None:
         nic.idx = nic_idx
         nic.pci = pci
-        result = self.rpc.call_hot_add_nic(self.instance.primary_node,
-                                           self.instance, nic, idx)
+        self.rpc.call_hot_add_nic(self.instance.primary_node,
+                                  self.instance, nic, idx)
     desc =  [
       ("nic.%d" % idx,
        "add:mac=%s,ip=%s,mode=%s,link=%s" %
@@ -12923,11 +12924,11 @@ class LUInstanceSetParams(LogicalUnit):
       self.LogInfo("Trying to hotplug device.")
       self.rpc.call_hot_del_nic(self.instance.primary_node,
                                 self.instance, nic, idx)
-      result = self.rpc.call_hot_add_nic(self.instance.primary_node,
-                                         self.instance, nic, idx)
+      self.rpc.call_hot_add_nic(self.instance.primary_node,
+                                self.instance, nic, idx)
     return changes
 
-  def _RemoveNic(self, idx, nic, private):
+  def _RemoveNic(self, idx, nic, _):
     if nic.pci and not self.op.hotplug:
       raise errors.OpPrereqError("Cannot remove a nic that has been hotplugged"
                                  " without removing it with hotplug",
diff --git a/lib/hypervisor/hv_kvm.py b/lib/hypervisor/hv_kvm.py
index 8e8e58c54450ec41bddca71262f9858f156942ba..ba12ad958f6fbe462cd26d0470ab71fc579c06e4 100644
--- a/lib/hypervisor/hv_kvm.py
+++ b/lib/hypervisor/hv_kvm.py
@@ -1039,9 +1039,8 @@ class KVMHypervisor(hv_base.BaseHypervisor):
     hvp = instance.hvparams
     kernel_path = hvp[constants.HV_KERNEL_PATH]
     if kernel_path:
-      boot_disk = boot_cdrom = boot_floppy = boot_network = False
+      boot_cdrom = boot_floppy = boot_network = False
     else:
-      boot_disk = hvp[constants.HV_BOOT_ORDER] == constants.HT_BO_DISK
       boot_cdrom = hvp[constants.HV_BOOT_ORDER] == constants.HT_BO_CDROM
       boot_floppy = hvp[constants.HV_BOOT_ORDER] == constants.HT_BO_FLOPPY
       boot_network = hvp[constants.HV_BOOT_ORDER] == constants.HT_BO_NETWORK
@@ -1400,7 +1399,6 @@ class KVMHypervisor(hv_base.BaseHypervisor):
     conf_hvp = instance.hvparams
     name = instance.name
     self._CheckDown(name)
-    boot_disk = conf_hvp[constants.HV_BOOT_ORDER] == constants.HT_BO_DISK
 
     temp_files = []
 
@@ -1627,12 +1625,12 @@ class KVMHypervisor(hv_base.BaseHypervisor):
 
     return result
 
-  def HotAddDisk(self, instance, disk, dev_path, seq):
+  def HotAddDisk(self, instance, disk, dev_path, _):
     """Hotadd new disk to the VM
 
     """
     if not self._InstancePidAlive(instance.name)[2]:
-      logging.info("Cannot hotplug. Instance %s not alive" % instance.name)
+      logging.info("Cannot hotplug. Instance %s not alive", instance.name)
       return disk.ToDict()
 
     _, v_major, v_min, _ = self._GetKVMVersion()
@@ -1641,16 +1639,16 @@ class KVMHypervisor(hv_base.BaseHypervisor):
       command = ("drive_add dummy file=%s,if=none,id=drive%d,format=raw" %
                  (dev_path, idx))
 
-      logging.info("%s" % command)
+      logging.info("Run cmd %s", command)
       output = self._CallMonitorCommand(instance.name, command)
 
       command = ("device_add virtio-blk-pci,bus=pci.0,addr=%s,"
                  "drive=drive%d,id=virtio-blk-pci.%d"
                  % (hex(disk.pci), idx, idx))
-      logging.info("%s" % command)
+      logging.info("Run cmd %s", command)
       output = self._CallMonitorCommand(instance.name, command)
       for line in output.stdout.splitlines():
-        logging.info("%s" % line)
+        logging.info("%s", line)
 
       (kvm_cmd, kvm_nics,
        hvparams, block_devices) = self._LoadKVMRuntime(instance)
@@ -1660,12 +1658,12 @@ class KVMHypervisor(hv_base.BaseHypervisor):
 
     return disk.ToDict()
 
-  def HotDelDisk(self, instance, disk, seq):
+  def HotDelDisk(self, instance, disk, _):
     """Hotdel disk to the VM
 
     """
     if not self._InstancePidAlive(instance.name)[2]:
-      logging.info("Cannot hotplug. Instance %s not alive" % instance.name)
+      logging.info("Cannot hotplug. Instance %s not alive", instance.name)
       return disk.ToDict()
 
     _, v_major, v_min, _ = self._GetKVMVersion()
@@ -1673,13 +1671,13 @@ class KVMHypervisor(hv_base.BaseHypervisor):
       idx = disk.idx
 
       command = "device_del virtio-blk-pci.%d" % idx
-      logging.info("%s" % command)
+      logging.info("Run cmd %s", command)
       output = self._CallMonitorCommand(instance.name, command)
       for line in output.stdout.splitlines():
-        logging.info("%s" % line)
+        logging.info("%s", line)
 
       command = "drive_del drive%d" % idx
-      logging.info("%s" % command)
+      logging.info("Run cmd %s", command)
       #output = self._CallMonitorCommand(instance.name, command)
       #for line in output.stdout.splitlines():
       #  logging.info("%s" % line)
@@ -1702,7 +1700,7 @@ class KVMHypervisor(hv_base.BaseHypervisor):
 
     """
     if not self._InstancePidAlive(instance.name)[2]:
-      logging.info("Cannot hotplug. Instance %s not alive" % instance.name)
+      logging.info("Cannot hotplug. Instance %s not alive", instance.name)
       return nic.ToDict()
 
     _, v_major, v_min, _ = self._GetKVMVersion()
@@ -1717,18 +1715,18 @@ class KVMHypervisor(hv_base.BaseHypervisor):
 
       command = ("netdev_add tap,id=netdev%d,fd=netdev%d"
                  % (idx, idx))
-      logging.info("%s" % command)
+      logging.info("Run cmd %s", command)
       output = self._CallMonitorCommand(instance.name, command)
       for line in output.stdout.splitlines():
-        logging.info("%s" % line)
+        logging.info("%s", line)
 
       command = ("device_add virtio-net-pci,bus=pci.0,addr=%s,mac=%s,"
                  "netdev=netdev%d,id=virtio-net-pci.%d"
                  % (hex(nic.pci), mac, idx, idx))
-      logging.info("%s" % command)
+      logging.info("Run cmd %s", command)
       output = self._CallMonitorCommand(instance.name, command)
       for line in output.stdout.splitlines():
-        logging.info("%s" % line)
+        logging.info("%s", line)
 
       self._ConfigureNIC(instance, seq, nic, tap)
 
@@ -1740,30 +1738,29 @@ class KVMHypervisor(hv_base.BaseHypervisor):
 
     return nic.ToDict()
 
-  def HotDelNic(self, instance, nic, seq):
+  def HotDelNic(self, instance, nic, _):
     """Hotadd new nic to the VM
 
     """
     if not self._InstancePidAlive(instance.name)[2]:
-      logging.info("Cannot hotplug. Instance %s not alive" % instance.name)
+      logging.info("Cannot hotplug. Instance %s not alive", instance.name)
       return nic.ToDict()
 
     _, v_major, v_min, _ = self._GetKVMVersion()
     if (v_major, v_min) >= (1, 0) and nic.pci:
-      mac = nic.mac
       idx = nic.idx
 
       command = "device_del virtio-net-pci.%d" % idx
-      logging.info("%s" % command)
+      logging.info("Run cmd %s", command)
       output = self._CallMonitorCommand(instance.name, command)
       for line in output.stdout.splitlines():
-        logging.info("%s" % line)
+        logging.info("%s", line)
 
       command = "netdev_del netdev%d" % idx
-      logging.info("%s" % command)
+      logging.info("Run cmd %s", command)
       output = self._CallMonitorCommand(instance.name, command)
       for line in output.stdout.splitlines():
-        logging.info("%s" % line)
+        logging.info("%s", line)
 
       (kvm_cmd, kvm_nics,
        hvparams, block_devices) = self._LoadKVMRuntime(instance)