diff -r 9f69fe562f0f nml/global_constants.py
--- a/nml/global_constants.py	Tue Sep 02 23:15:10 2014 +0200
+++ b/nml/global_constants.py	Sat Sep 20 20:50:00 2014 +0200
@@ -1136,7 +1136,7 @@
 }
 
 def config_flag_read(bit, pos):
-    return expression.BinOp(nmlop.HASBIT, expression.Parameter(expression.ConstantNumeric(0x85), pos), expression.ConstantNumeric(bit), pos)
+    return expression.SpecialCheck((0x01, r'\70'), 0x85, (0, 1), bit, "PatchFlag({})".format(bit), pos = pos)
 
 def config_flag(info, pos):
     return expression.SpecialParameter(generic.reverse_lookup(config_flags, info), info, None, config_flag_read, True, pos)