Linux Linaro STE Snowball ubuntu image deploy failed since build 257.

On STE Snowball board, Linux Linaro ubuntu image deploy failed since build 257:

http://validation.linaro.org/lava-server/dashboard/streams/private/team/linaro/pre-built-leb-snowball/bundles/4eab182b989ca026cf2e3332bcdc4469b91ae04b/5308780c-8ccd-11e2-9729-68b599be548c/

Lava failed at action deploy_linaro_image with error:Unable to mount image /linaro/images/tmp/tmpkxoxeK/snowball-quantal_developer_20130227-257.img at offset None
Traceback (most recent call last):
  File "/srv/lava<email address hidden>/lava_dispatcher/job.py", line 177, in run
    action.run(**params)
  File "/srv/lava<email address hidden>/lava_dispatcher/actions/deploy.py", line 75, in run
    hwpack=hwpack, rootfs=rootfs, image=image, rootfstype=rootfstype, bootloader=bootloader)
  File "/srv/lava<email address hidden>/lava_dispatcher/client/targetdevice.py", line 66, in deploy_linaro
    self.target_device.deploy_linaro_prebuilt(image)
  File "/srv/lava<email address hidden>/lava_dispatcher/device/master.py", line 148, in deploy_linaro_prebuilt
    (boot_tgz, root_tgz, data) = self._generate_tarballs(image_file)
  File "/srv/lava<email address hidden>/lava_dispatcher/device/master.py", line 178, in _generate_tarballs
    self._customize_linux(image_file)
  File "/srv/lava<email address hidden>/lava_dispatcher/device/target.py", line 169, in _customize_linux
    with image_partition_mounted(image, root_part) as mnt:
  File "/usr/lib/python2.7/contextlib.py", line 17, in __enter__
    return self.gen.next()
  File "/srv/lava<email address hidden>/lava_dispatcher/client/lmc_utils.py", line 93, in image_partition_mounted
    image, offset))
RuntimeError: Unable to mount image /linaro/images/tmp/tmpkxoxeK/snowball-quantal_developer_20130227-257.img at offset None