diff --git a/daemon/core/nodes/interface.py b/daemon/core/nodes/interface.py
index deaaf261..5424bc1b 100644
--- a/daemon/core/nodes/interface.py
+++ b/daemon/core/nodes/interface.py
@@ -141,8 +141,11 @@ class CoreInterface(object):
         :return: True if parameter changed, False otherwise
         """
         # treat None and 0 as unchanged values
+        if value is None or value <= 0:
+            return False
+
         current_value = self._params.get(key)
-        if value is None or current_value == value or current_value <= 0 and value <= 0:
+        if current_value is not None and current_value == value:
             return False
 
         self._params[key] = value
diff --git a/daemon/core/nodes/ipaddress.py b/daemon/core/nodes/ipaddress.py
index 23144ce1..f1a763d1 100644
--- a/daemon/core/nodes/ipaddress.py
+++ b/daemon/core/nodes/ipaddress.py
@@ -236,7 +236,7 @@ class IpPrefix(object):
             self.prefixlen = int(tmp[1])
         else:
             self.prefixlen = self.addrlen
-        self.prefix = socket.inet_pton(self.af, tmp[0]).decode("ISO-8859-1")
+        self.prefix = socket.inet_pton(self.af, tmp[0])
         if self.addrlen > self.prefixlen:
             addrbits = self.addrlen - self.prefixlen
             netmask = ((1 << self.prefixlen) - 1) << addrbits