[Solved]Can't get Debian to boot on NSA325 (no replies)

Hello,

I tried to boot Debian on my NSA 325 following this guide http://zyxel.nas-central.org/wiki/Debian_on_325
Unfortunately I can't get Debian to boot up. Everytime I try to boot the USB stick I get the following message:

Hit any key to stop autoboot:  0
(Re)start USB...
USB:   scanning bus for devices... 3 USB Device(s) found
Waiting for storage device(s) to settle before scanning...
T Device NOT ready
   Request Sense returned 00 00 00
1 Storage Device(s) found
** Bad partition 1 **
** Bad partition 1 **
## Booting image at 02000000 ...
Bad Magic Number
Marvell>>

I formatted the USB drive using gparted.
What am I doing wrong?

EDIT:
It's working now. I tried another USB stick which worked right away.