I have the same problem but i have a TMS cable for my w810. I need to flash the gdfs on it as it is currently bricked. I have tried everything else with various software and can successfully :

Load MAIN and FS and finalize

Load new eeprom

Unlock fone and rebuild sp area.

I have tried changing the main AND fs into RCK003 AND ALSO R4CE012 which are compatible with SEMCTOOL 8.4 FREE version but it fails giving me an error.

If i try new firmware it says its not compatible.

I am also able to connect to sony update service and update my fone but still it shows me a white screen.

Im sure its not hardware as the other day i got the please wait message on the screen.

Any ideas anyone? anyway of updating gdfs --- i have the gdfs in bin gdfs and ssw format.