--- a/pvl/hosts/dhcp.py	Mon Mar 02 19:58:12 2015 +0200
+++ b/pvl/hosts/dhcp.py	Mon Mar 02 19:58:35 2015 +0200
@@ -7,10 +7,10 @@
     """
     
     # hardware-type prefixed hardware-address
-    hardware = pvl.dhcp.config.Field('1:' + ethernet)
+    hardware = '1:' + ethernet
 
     return pvl.dhcp.config.Block(None, [
-        ('subclass', subclass, hardware),
+        ('subclass', pvl.dhcp.config.String(subclass), pvl.dhcp.config.Field(hardware)),
     ])
 
 class HostDHCPError(pvl.hosts.host.HostError):