error while booting NSA320 from USB drive

Hi,

I am trying to install debian on a NSA320. I extracted the latest rootfs (Debian-3.13.1-kirkwood-tld-2-rootfs-bodhi.tar.bz2 (07 Feb 2014)) to a usb thumb drive. It starts to boot correctly. It detects the two hard drives and the usb thumb drive but at some point, I get some errors and I get stuck in the initramfs. Any idea what can cause this? Here is the section of the log where the error happens.

Begin: Loading essential drivers ... done.
Begin: Running /scripts/init-premount ... done.
Begin: Mounting root file system ... Begin: Running /scripts/local-top ... done.
Begin: Running /scripts/local-premount ... done.
mount: mounting rootfs on /root failed: No such file or directory
Begin: Running /scripts/local-bottom ... done.
done.
Begin: Running /scripts/init-bottom ... mount: mounting /dev on /root/dev failed: No such file or directory
done.
Target filesystem doesn't have requested /sbin/init.
No init found. Try passing init= bootarg.
modprobe: module i8042 not found in modules.dep
[ 30.705422] uhci_hcd: USB Universal Host Controller Interface driver
[ 30.718492] ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver
[ 30.734220] hidraw: raw HID events driver (C) Jiri Kosina
[ 30.741803] usbcore: registered new interface driver usbhid
[ 30.747401] usbhid: USB HID core driver


BusyBox v1.20.2 (Debian 1:1.20.0-7) built-in shell (ash)
Enter 'help' for a list of built-in commands.

/bin/sh: can't access tty; job control turned off
(initramfs)