Failed test: http://chromeos-autotest.hot.corp.google.com/afe/#tab_id=view_job&object_id=5901

Symptom:
    File "/usr/local/autotest/client/common_lib/test.py", line 804, in _call_test_function
      return func(*args, **dargs)
    File "/usr/local/autotest/client/common_lib/test.py", line 461, in execute
      dargs)
    File "/usr/local/autotest/client/common_lib/test.py", line 347, in _call_run_once_with_retry
      postprocess_profiled_run, args, dargs)
    File "/usr/local/autotest/client/common_lib/test.py", line 376, in _call_run_once
      self.run_once(*args, **dargs)
    File "/usr/local/autotest/server/site_tests/provision_AutoUpdate/provision_AutoUpdate.py", line 147, in run_once
      force_full_update=force)
    File "/usr/local/autotest/server/afe_utils.py", line 237, in machine_install_and_update_labels
      *args, **dargs)
    File "/usr/local/autotest/server/hosts/cros_host.py", line 719, in machine_install_by_devserver
      full_update=force_full_update)
    File "/usr/local/autotest/client/common_lib/cros/dev_server.py", line 1813, in auto_update
      error_msg % (host_name, 'has reached AU retry limit.'))
  DevServerException: CrOS auto-update failed for host chromeos2-row9-rack1-host9: has reached AU retry limit.


Looking at the client logs for the test, we tried autoupdate via the old flow with devserver 100.115.245.198 twice, then bailed.

The devserver's (collected) autoupdate logs suddenly go silent when trying to copy stateful.tgz to the DUT.

Note that the DUT was successfully provisioned to gandof-release/R54-8743.76.0 before the test. The test tries to autoupdate the DUT twice from this provisioned version to the target version, and once again a trivial autoupdate to the same version. The test failed when attempting the first autoupdate to version R54-8743.76.0

Logs to successful provision: https://pantheon.corp.google.com/storage/browser/chromeos-autotest-results/hosts/chromeos2-row9-rack1-host9/11758-provision
Logs to failed test: https://pantheon.corp.google.com/storage/browser/chromeos-autotest-results/5901-chromeos-test/chromeos2-row9-rack1-host9/