BMV712 frozen , cannot up-date firm ware to 4.3. New install

New install. Inital power up , all looked good. from my I phone , blue tooth sync all good. Went for the first up-date , all good. Then when it went for update from 4.0 to 4.3 it stops each time at exactly 68%. Screen is frozen. Cannot get Setup / Select to re-set display. The back light stays on all of the time. I do know that my I phone wi fi is only at 1 bar at site location. Is it possible that another device with stronger wi fi will install 4.3 . I Phone says no 4.0 installed now. Note : I have tried unplugging RJ plug from Both Ends ,and also power cable from Shunt. Still same result .