my apple tv won't boot anymore

Hello,
I just upgrade to the latest version 3.6.4 and I use the new feature (USB storage).
I boot on my external drive and after two day I coulnd connect trough FTP anymore.

At that point I have done something wrong I tried to revers the booting option on the internal and since then my apple tv is stuck on the apple logo.
I can’t do anything… I tried to re Flash the Apple tv and reboot but it doesnt change anything…

Can someone help me ???

Thanks

Isma

Using an external drive as primary storage requires the drive to be connected at all times.You’ll ensure the external drive is powered on and connected before the AppleTV is started up.