QFX5100 switch is stuck in a boot loop after attempting to reboot/power cycle the switch.

QFX5100 switch is stuck in a boot loop after attempting to reboot/power cycle the switch. The error message we are receiving is as follows:
 

Trying to mount root from ufs:/dev/ad0s1a


Manual root filesystem specification:

 <fstype>:<device> Mount <device> using filesystem <fstype>

            eg. ufs:ad0s1a

 ?         List valid disk boot devices

 <empty line>    Abort manual input



mountroot> 

swapper pid 1 tid 100007 ran for 33806 ms

panic: Root mount failed, startup aborted.

Cannot dump. No dump device defined.

Automatic reboot in 15 seconds - press a key on the console to abort

Rebooting...

In some cases, switch try to auto reboot and ends up again into the mountroot> prompt.

Solution:

* Try to execute the command “boot or reboot” when stuck in mountroot mode.

mountroot>boot

OR

mountroot>reboot

* If the switch continue to get stuck in mount root mode, try to power-cycle the switch.

* If power-cycle does not resolve the issue, try Junos recovery.

If the above option do not resolve the issue, Replace the switch.