firmware_FwScreenPressPower on M61 (ToT)

logs https://pantheon.corp.google.com/storage/browser/chromeos-autotest-results/127911971-chromeos-test/chromeos4-row2-rack11-host11

Error complain about 'mount: special device /dev/sda3 does not exist'

AutoservRunError: command execution error
* Command: 
    /usr/bin/ssh -a -x   -o StrictHostKeyChecking=no -o
    UserKnownHostsFile=/dev/null -o BatchMode=yes -o ConnectTimeout=30 -o
    ServerAliveInterval=180 -o ServerAliveCountMax=3 -o ConnectionAttempts=4
    -o Protocol=2 -l root -p 22 chromeos4-row2-rack11-host11-servo " if type
    \"logger\" > /dev/null 2>&1; then logger -tag \"autotest\"
    \"server[stack::run|run|wrapper] -> ssh_run(mount -o ro /dev/sda3
    /tmp/usbcheck.oXjK)\";fi; mount -o ro /dev/sda3 /tmp/usbcheck.oXjK"
Exit status: 32
Duration: 1.25736093521

stderr:
mount: special device /dev/sda3 does not exist


This was passing on mccloud for a few time around 9719.0 (but never pass on mickey)
https://cros-goldeneye.corp.google.com/chromeos/healthmonitoring/testDetails?testName=firmware_FwScreenPressPower.dev&suite=faft_bios&daysBack=30&board=&architecture=&boardFamily=&buildConfig=&reason=&version=&milestone=&dut=