W850 Flashing White Screen After Full Flash

[onlyone]

you said you wanted to restore gdfs
so it means that you have a copy of your gdfs is that correct?
if so, try to flash back that copy and everything should go fine

[h4$_426]

I have tried that but still same problem

[ts014]

your gdfs is damaged, try this How to Repair a db2020 GDFS - Top Sony Forums

borrow your friends cruiser cable and try to repair the gdfs following the guide cruiser cable will give better results than the dcu-60.