diff --git a/roundup/cgi/ZTUtils/Batch.py b/roundup/cgi/ZTUtils/Batch.py
index 66dde68..e0647e6 100644
--- a/roundup/cgi/ZTUtils/Batch.py
+++ b/roundup/cgi/ZTUtils/Batch.py
@@ -92,7 +92,9 @@ class Batch:
 
 def opt(start,end,size,orphan,sequence):
     if size < 1:
-        if start > 0 and end > 0 and end >= start:
+        if size == -1:
+            size=len(sequence)
+        elif start > 0 and end > 0 and end >= start:
             size=end+1-start
         else: size=7
 
diff --git a/roundup/cgi/templating.py b/roundup/cgi/templating.py
index deacc88..4d9ef79 100644
--- a//roundup/cgi/templating.py
+++ b//roundup/cgi/templating.py
@@ -2812,6 +2812,11 @@ class Batch(ZTUtils.Batch):
     def previous(self):
         if self.start == 1:
             return None
+
+        if self._size == -1:
+            return Batch(self.client, self._sequence, self._size,
+                0, 0, self.orphan, self.overlap)
+
         return Batch(self.client, self._sequence, self._size,
             self.first - self._size + self.overlap, 0, self.orphan,
             self.overlap)