How to train GoogleNet using ImageData layer with grayscale images?

[mintaka]

I'd like to train a GoogleNet model using grayscale images. I'm using the latest master branch. I've specified `is_color: false` in the ImageData layer as follows:

layer {
  name: "data"
  type: "ImageData"
  top: "data"
  top: "label"
  include {
    phase: TRAIN
  }
  transform_param {
    mirror: true
    crop_size: 224
    mean_value: 104
    mean_value: 117
    mean_value: 123
  }
  image_data_param {
    source: "/path/to/image_list.txt"
    batch_size: 20
    new_height: 256
    new_width: 256
    is_color: false
  }
}

However, when I started to train from scratch or fine-tune (based on the standard pre-trained GoogleNet model using ImageNet) a GoogleNet model, the program got aborted when initializing GoogleNet.

May anyone help point out what I did wrong?

Thanks in advance.