diff --git a/convert.lua b/convert.lua
index a64dfe2..2c5ef1a 100644
--- a/convert.lua
+++ b/convert.lua
@@ -15,6 +15,21 @@ local layer_list = {
   'VolumetricAveragePooling',
 }
 
+local layer_isize = {
+  {'SpatialConvolution', 4},
+  {'SpatialCrossMapLRN', 4},
+  {'SpatialFullConvolution', 4},
+  {'SpatialMaxPooling', 4},
+  {'SpatialAveragePooling', 4},
+  {'SpatialDivisiveNormalization', 4},
+  {'SoftMax', 4},
+  {'LogSoftMax', 4},
+  {'TemporalConvolution', 4},
+  {'VolumetricConvolution', 5},
+  {'VolumetricMaxPooling', 5},
+  {'VolumetricAveragePooling', 5},
+}
+
 -- similar to nn.Module.apply
 -- goes over a net and recursively replaces modules
 -- using callback function
@@ -56,12 +71,27 @@ function cudnn.convert(net, dst)
       y = convert('SpatialCrossMapLRN')
     else
       for i,v in ipairs(layer_list) do
-        if torch.typename(x) == src_prefix..v then
+        if t == src_prefix..v then
           y = convert(v)
         end
       end
     end
-    return y == 0 and x or y
+    if y == 0 then y = x end
+
+    -- hacky code to initialize iSize
+    if src == nn then
+      t = torch.typename(y)
+      if t == 'cudnn.SpatialBatchNormalization' or t == 'cudnn.VolumetricBatchNormalization' then
+        y.iSize = torch.LongStorage(y.nDim):fill(0)
+      else
+        for i,v in ipairs(layer_isize) do
+          if t == dst_prefix..v[1] then
+            y.iSize = torch.LongStorage(v[2]):fill(0)
+          end
+        end
+      end
+    end
+    return y
   end)
 end