You May Use XS++3.1 Which Is Entirely Free. But If Your EROM Is Dead, You Need To Repair It. If Theres A Red Diode Blinking In InfraPort, You Need To Repair EROM If Not Than Just Reflashing Will Solve Your Problem.
Repairing EROM:
REPAIRING EROM GUIDES for most sonyericsson phones - Top Sony Forums
Flashing For FREE Via XS++3.1:
XS++ 3.1 Guide-Flashing,Customizing,Recovering - Top Sony Forums