EX6100 factory reset fails

Hi, I was updating the firmware on my EX6100 which seemed to stall for an extended period. I power cycled the device and when it didn't respond, I attempted a factory reset. Unfortunately, it doesn't seem to be responding to that either, with the power led just flashing green. No amber reset led indicator or reboot. Is there a harder reset for a failed firmware upgrade or do I have to throw it away? Cheers, S