diff --git a/src/calibre/customize/profiles.py b/src/calibre/customize/profiles.py
index 402dd35f45..4d8b8a0113 100644
--- a/src/calibre/customize/profiles.py
+++ b/src/calibre/customize/profiles.py
@@ -244,7 +244,7 @@ class KindleDXOutput(OutputProfile):
     # Screen size is a best guess
     screen_size               = (744, 1022)
     dpi                       = 150.0
-    comic_screen_size         = (744, 1022)
+    comic_screen_size         = (741, 1022)
 
     @classmethod
     def tags_to_string(cls, tags):
diff --git a/src/calibre/ebooks/conversion/preprocess.py b/src/calibre/ebooks/conversion/preprocess.py
index cad247c48d..82637016cc 100644
--- a/src/calibre/ebooks/conversion/preprocess.py
+++ b/src/calibre/ebooks/conversion/preprocess.py
@@ -56,6 +56,7 @@ def line_length(raw, percent):
     if not lengths:
         return 0
 
+    lengths = list(set(lengths))
     total = sum(lengths)
     avg = total / len(lengths)
     max_line = avg * 2
@@ -189,7 +190,7 @@ class HTMLPreProcessor(object):
             if length:
                 line_length_rules = [
                     # Un wrap using punctuation
-                    (re.compile(r'(?<=.{%i}[a-z,;:-IA])\s*(?P<ital></(i|b|u)>)?\s*(<p.*?>)\s*(?=(<(i|b|u)>)?[\w\d])' % length, re.UNICODE), wrap_lines),
+                    (re.compile(r'(?<=.{%i}[a-z\.,;:)-IA])\s*(?P<ital></(i|b|u)>)?\s*(<p.*?>)\s*(?=(<(i|b|u)>)?\s*[\w\d(])' % length, re.UNICODE), wrap_lines),
                 ]
 
             rules = self.PDFTOHTML + line_length_rules
diff --git a/src/calibre/ebooks/oeb/iterator.py b/src/calibre/ebooks/oeb/iterator.py
index af8dd84162..2b68b6cf57 100644
--- a/src/calibre/ebooks/oeb/iterator.py
+++ b/src/calibre/ebooks/oeb/iterator.py
@@ -135,7 +135,7 @@ class EbookIterator(object):
                 plumber.opts, plumber.input_fmt, self.log,
                 {}, self.base)
 
-        if plumber.input_fmt.lower() == 'pdf':
+        if plumber.input_fmt.lower() in ('pdf', 'rb'):
             self.pathtoopf = create_oebbook(self.log, self.pathtoopf, plumber.opts,
                     plumber.input_plugin)
         if hasattr(self.pathtoopf, 'manifest'):
diff --git a/src/calibre/gui2/convert/txt_output.py b/src/calibre/gui2/convert/txt_output.py
index dd36dc8cfc..b3a79e1326 100644
--- a/src/calibre/gui2/convert/txt_output.py
+++ b/src/calibre/gui2/convert/txt_output.py
@@ -30,5 +30,5 @@ class PluginWidget(Widget, Ui_Form):
         self.opt_newline.setModel(self.newline_model)
 
         default_index = self.opt_newline.findText(default)
-        self.opt_newline.setCurrentIndex(default_index if default_index != -1 else 0)
-
+        system_index = self.opt_newline.findText('system')
+        self.opt_newline.setCurrentIndex(default_index if default_index != -1 else system_index if system_index != -1 else 0)