Do we have some solution to bring back to life nuvi who wont turn on?

My friend have one nuvi 250W flashed to 465,after flash is over he have with screen and then nuvi turn off.
Now nuvi wont turn on,on button,when is connected to PC and reset button also wont work.
China GPS have jtag solution,do we have also this solution on Garmin or is only solution to replace chip?