diff --git a/tailbone/templates/mobile/batch/inventory/view_row.mako b/tailbone/templates/mobile/batch/inventory/view_row.mako
index d4d49f75..8643da1e 100644
--- a/tailbone/templates/mobile/batch/inventory/view_row.mako
+++ b/tailbone/templates/mobile/batch/inventory/view_row.mako
@@ -53,7 +53,17 @@
     % endif
     ${h.hidden('units')}
 
-    ${keypad(unit_uom, uom, quantity=(row.cases or row.units or 1) if allow_cases else (row.units or 1), allow_cases=allow_cases)}
+    <%
+       quantity = 1
+       if allow_cases:
+           if row.cases is not None:
+               quantity = row.cases
+           elif row.units is not None:
+               quantity = row.units
+       elif row.units is not None:
+           quantity = row.units
+    %>
+    ${keypad(unit_uom, uom, quantity=quantity, allow_cases=allow_cases)}
 
     <fieldset data-role="controlgroup" data-type="horizontal" class="inventory-actions">
       <button type="button" class="ui-btn-inline ui-corner-all save">Save</button>
diff --git a/tailbone/templates/mobile/keypad.mako b/tailbone/templates/mobile/keypad.mako
index 8f0f131d..38cb03da 100644
--- a/tailbone/templates/mobile/keypad.mako
+++ b/tailbone/templates/mobile/keypad.mako
@@ -29,7 +29,7 @@
     </table>
 
     <fieldset data-role="controlgroup" data-type="horizontal">
-      <button type="button" class="ui-btn-active keypad-quantity">${h.pretty_quantity(quantity or 1)}</button>
+      <button type="button" class="ui-btn-active keypad-quantity">${h.pretty_quantity(1 if quantity is None else quantity)}</button>
       <button type="button" disabled="disabled">&nbsp;</button>
       % if allow_cases:
       ${h.radio('keypad-uom', value='CS', checked=selected_uom == 'CS', label="CS")}
diff --git a/tailbone/views/inventory.py b/tailbone/views/inventory.py
index 6c0a16c2..57dcae36 100644
--- a/tailbone/views/inventory.py
+++ b/tailbone/views/inventory.py
@@ -588,12 +588,14 @@ class InventoryBatchView(BatchMasterView):
                 row = self.Session.query(model.InventoryBatchRow).get(update_form.validated['row'])
                 cases = update_form.validated['cases']
                 units = update_form.validated['units']
-                if cases:
+                if cases is not colander.null:
                     row.cases = cases
                     row.units = None
-                elif units:
+                elif units is not colander.null:
                     row.cases = None
                     row.units = units
+                else:
+                    raise NotImplementedError
                 self.handler.refresh_row(row)
                 route_prefix = self.get_route_prefix()
                 return self.redirect(self.request.route_url('mobile.{}.view'.format(route_prefix), uuid=batch.uuid))