OpenBrick NG, USB hard drive and Debian Sarge

Hello List,

since a while I have tried to run Sarge on my openbrick
with an external USB hard drive.

First, I installed an internal ide2 hard drive inside the box:
everything was working well. Now I am trying to migrate
to a USB external hard drive:
right now the main issue is that the initrd stuff does not succeed to 
mount the root directory during the pivot_root stage.
Any idea ?
Any success story with Debian ?

Thanks in advance,
Jerome