Unhappy [Q] SGP 312 bricked, HELP!

Hi guys...
After installed last available dual recovery CWM-TWRP dual recovery on my SGP 312, with a rooted 4.3 stock rom, the result is... BRICKED!
There the SONY logo booting and nothing else, not even been able to power off the device.
The only thing I've seen having some effect is PWR+Vol.UP wich seems to reboot, but nothing else. If I connect to flashtool is not able to recognize the device attached to my PC.

Any ideas?

Thanks...