[Q] Bricked LG G2 in fastboot topic

Hi,
I'm in serious troubles with my LG G2 (D802) Europe version (bought in Italy): after flashing a custom ROM, I pressed on "reboot" button of the recovery and the phone rebooted with a totally black screen and a white text at the upper left corner

"[1660] Fastboot mode started".

If I press on the power button for a while, it restarts and goes back to the same screen. If I press power button *and* volume up, the same. The same by pressing with volume down or pressing all the buttons.

If I connect to the PC it writes on the screen 5 more lines:
[509280] -- reset --
[509290] -- portcharge --
[513820] -- reset --
[513830] -- portcharge --
[513900] fastboot: processing commands

I read on Internet that a similar issue has been solved by doing:

fastboot erase laf
fastboot flash laf laf.img
fastboot reboot

but in my case after the reboot the screen goes back to the "Fastboot mode started". BTW, "fastboot devices" fires out:

???????????? fastboot

but fastboot can still do something on the phone, like flashing the laf, the boot, the recovery... in fact I flashed aboot, boot, recovery, laf but after reboot the phone was still stuck.

Is the devices completely lost or there's something I can do to recover it ?

thanks !