[Q] Fastboot freezes topic

Hi people,
I have Samsung Google Nexus, rooted, on Paranoid Android 4.0 beta3, CWM 6.0.4.3.

The problem is when I rebooting my phone into Fastboot my volume and power keys do not respond at all, and I need to unplug my battery to reboot again...

Does anyone know something about this problem and can help?

Thanks