Problem with RBcAP2nd: all leds on. Unable Netinstall

Dear all,
I have a problem with my RBcAP2nD.
A few days ago I try to upgrade to last stable software version. When I done that the RBcAP2nD didn’t reboot and all leds come on.
I tryed to reboot cutting power but unable!
I tryed to make a reset for more then 5 seconds but also Netinstall is unable to discovery the routerboard.
When I keep reset (power off, then keep press reset until led flashng), Netinstall is unable to discovery the routerboard, the when I relese the reset key, all leds come on.

Someone can help me?
Best Regards
Luca