Some of the DUTs in the lab failed to repair. As the new-added check of EC existence requires executing the command "mosys ec info" on DUT; however, the DUT may be offline.

For example: https://pantheon.corp.google.com/storage/browser/chromeos-autotest-results/hosts/chromeos1-row1-rack10-host4/55151442-repair/debug/

05/10 11:15:29.412 INFO |      abstract_ssh:0735| Master ssh connection to chromeos1-row1-rack10-host4 is down.
05/10 11:15:30.415 INFO |      abstract_ssh:0749| Starting master ssh connection '/usr/bin/ssh -a -x   -N -o ControlMaster=yes -o ControlPath=/tmp/_autotmp_ECzVIxssh-master/socket -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -o BatchMode=yes -o ConnectTimeout=30 -o ServerAliveInterval=900 -o ServerAliveCountMax=3 -o ConnectionAttempts=4 -o Protocol=2 -l root -p 22 chromeos1-row1-rack10-host4'
05/10 11:15:35.462 INFO |      abstract_ssh:0764| Timed out waiting for master-ssh connection to be established.
05/10 11:17:38.921 ERROR|            repair:0397| Repair failed: Re-install the stable firmware
Traceback (most recent call last):
  File "/usr/local/autotest/client/common_lib/hosts/repair.py", line 395, in _repair_host
    self.repair(host)
  File "/usr/local/autotest/server/hosts/cros_repair.py", line 280, in repair
    host.firmware_install()
  File "/usr/local/autotest/server/hosts/cros_host.py", line 892, in firmware_install
    if self.get_ec():
  File "/usr/local/autotest/server/hosts/cros_host.py", line 1909, in get_ec
    ecinfo = self.run(command=cmd, ignore_status=True)
  File "/usr/local/autotest/server/hosts/ssh_host.py", line 190, in run
    options, stdin, args, ignore_timeout)
  File "/usr/local/autotest/server/hosts/ssh_host.py", line 151, in _run
    raise error.AutoservSSHTimeout("ssh timed out", result)
AutoservSSHTimeout: ('ssh timed out', * Command: 
    /usr/bin/ssh -a -x    -o ControlPath=/tmp/_autotmp_ECzVIxssh-
    master/socket -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null
    -o BatchMode=yes -o ConnectTimeout=30 -o ServerAliveInterval=900 -o
    ServerAliveCountMax=3 -o ConnectionAttempts=4 -o Protocol=2 -l root -p 22
    chromeos1-row1-rack10-host4 "export LIBC_FATAL_STDERR_=1; if type
    \"logger\" > /dev/null 2>&1; then logger -tag \"autotest\"
    \"server[stack::repair|firmware_install|get_ec] -> ssh_run(mosys ec
    info)\";fi; mosys ec info"
Exit status: 255
Duration: 123.418763161

stderr:
ssh: connect to host chromeos1-row1-rack10-host4 port 22: Connection timed out)
05/10 11:17:38.924 INFO |        server_job:0128| 		FAIL	----	repair.firmware	timestamp=1462904258	localtime=May 10 11:17:38	('ssh timed out', * Command: 
      /usr/bin/ssh -a -x    -o ControlPath=/tmp/_autotmp_ECzVIxssh-
      master/socket -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null
      -o BatchMode=yes -o ConnectTimeout=30 -o ServerAliveInterval=900 -o
      ServerAliveCountMax=3 -o ConnectionAttempts=4 -o Protocol=2 -l root -p 22
      chromeos1-row1-rack10-host4 "export LIBC_FATAL_STDERR_=1; if type
      \"logger\" > /dev/null 2>&1; then logger -tag \"autotest\"
      \"server[stack::repair|firmware_install|get_ec] -> ssh_run(mosys ec
      info)\";fi; mosys ec info"
  Exit status: 255
  Duration: 123.418763161
  
  stderr:
  ssh: connect to host chromeos1-row1-rack10-host4 port 22: Connection timed out)
05/10 11:17:38.925 INFO |        server_job:0128| 	END FAIL	----	repair.firmware	timestamp=1462904258	localtime=May 10 11:17:38

Should use other way to check the EC existence, like FAFT config.