Shenson:
I've done a few tests:
Tools :
- 4-5 pins soldered cable.
- 4 ports hub
- Portable battery (output:5v.Can charge the n800 with it)
- Hub power adapter
- 80 Gb 2.5 HD

* Using the portable battery to power the hd or the hub with the hd attached, made the "unrecognised device", and then the "unknow filesystem" appear, but *nothing else*.No reboot,tho.

* Using the Hub power adapter for powering the hd, or the hub with the hd attached, made both messages appear, but the filemanager opens successfully.

So: if you get both messages, but the hd doesnt get mounted, maybe the hd is not being properly powered.My portable battery doesnt provide enough juice for the hd *sigh*