Hello, my gps enter on preeboot mode and try cure the firmware but nothing happends when try to cure the software missing appers and disconnect the garmin preboot mode, when reboots always put in calibration mode and if i boot with the usb connected freeze on the screen garmin and the load bar and do no detect as mass storage

the data from the g7towin is

nuvi 2 series software version 6.50 hwid:1091

tryied differentes firmwares but nothing happens i think there is a s4 board, but i can't see the way to know this because dont boot.
and i dont know the procedence because i buyed used with this problem

Thanks in advance