I tried to setup the M9 plus in my new place, however there is one (out of three) got bricked or loop, when I reset it.

The LED light goes amber(solid yellow) then goes off. If I replug the power, it still has the same behavior.

I have tried with the firmware recovery method, no luck at all.

The wired thing is if I hold the reset button longer than 10 seconds while plugging in the power, the LED turns purple (not solid red). 

Can someone help me with this ? I have no idea what is going on...