first of all:if u tryed to update from t68 2 t68i this is how u solve it
Upload flash avr(which version u want),
upload flash arm(same version as main flash avr)
also write gdfs file in phone
After all done, remove battery, put it back and hold NO for about 20 sec presed. In this time the phone is doing auto check and maybe thats why is not powering on.
if u just update, als is better to try like this
Best regardes,