Revived W850i white screen with UB.Here is how...
 

Problem with GDFS aparently...

Tried flashing all sorts of firmwares, generic, cust etc , converted from cid49 to cid52 still no succes :(

Then i read GDFS and save it for backup.
Flashed it with k800 GDFS, phone alive but hang on certan point.
Flashed back original GDFS and phone work fine :)

NOTE: WHEN UB ASK YOU DO YOU WATH TO OVERWRITE SECURITY ZONE SAY NO!!!!!

I know this is old post, but if someone can let me know what the hack is UB ?