Ok, a więc próbowałem metody z wątku http://eko.one.pl/forum/viewtopic.php?id=50.
Niestety ten skrypt u mnie nie działa 
Po rebocie widzę :
BusyBox v1.11.2 (2009-08-25 21:05:04 CEST) built-in shell (ash)
Enter 'help' for a list of built-in commands.
_______ ________ __
| |.-----.-----.-----.| | | |.----.| |_
| - || _ | -__| || | | || _|| _|
|_______|| __|_____|__|__||________||__| |____|
|__| W I R E L E S S F R E E D O M
KAMIKAZE (8.09.1, r17398) ----------------------------
* 10 oz Vodka Shake well with ice and strain
* 10 oz Triple sec mixture into 10 shot glasses.
* 10 oz lime juice Salute!
---------------------------------------------------
root@OpenWrt:~# df -h
Filesystem Size Used Available Use% Mounted on
rootfs 1.6M 1.6M 0 100% /
/dev/root 1.6M 1.6M 0 100% /rom
tmpfs 7.0M 40.0k 7.0M 1% /tmp
/dev/mtdblock/4 1.7M 408.0k 1.3M 24% /jffs
mini_fo:/jffs 1.6M 1.6M 0 100% /
Tak wygląda mój /sbin/init :
#!/bin/sh
# /sbin/init in internal flash
boot_dev="/dev/scsi/host0/bus0/target0/lun0/part2"
# load all needed modules
#for module in usbcore uhci scsi_mod sd_mod usb-storage ehci-hcd jbd ext3 # - us
for module in usbcore ohci scsi_mod usb-storage ext2 # - or use
do
insmod $module
done
# if disk is slow let him init
sleep 4s
mount "$boot_dev" /mnt
# if all ok (usb exists and last run external has seen lan), do the pivot root
if [ -x /mnt/sbin/init -a ! -e /mnt/sbin/donotrunexternal ]
then
mount -o move /proc /mnt/proc && \
/sbin/pivot_root /mnt /mnt/mnt && {
mount -o move /mnt/dev /dev
mount -o move /mnt/tmp /tmp
mount -o move /mnt/jffs2 /jffs2 2>&-
mount -o move /mnt/sys /sys 2>&-
}
else # if something wrong, clean changes
umount /mnt
fi
# run the real init on the end (from USB hopefully)
exec /bin/busybox init
Gdy odpalam ręcznie ten /sbin/init to:
root@OpenWrt:/sbin# ./init
insmod: a module named usbcore already exists
insmod: Loading module failed: No such file or directory #to akurat nieistotne :P
insmod: a module named scsi_mod already exists
insmod: a module named usb-storage already exists
insmod: a module named ext2 already exists
mount: /proc is not a block device
BusyBox v1.11.2 (2009-08-25 21:05:04 CEST) multi-call binary
Usage: init
Init is the parent of all processes
Jak to się wyświetli to już nic się nie dzieje, mogę to tylko zakończyć ctrl+c.
Mój OpenWRT to Kamikadze 8.09.
Używam pendrive'a 2GB, part1 to swap kilkumegowy, który kiedyś może użyje, part 2 to ext2.
On po zamontowaniu:
root@OpenWrt:/sbin# df -h
Filesystem Size Used Available Use% Mounted on
rootfs 1.6M 1.6M 0 100% /
/dev/root 1.6M 1.6M 0 100% /rom
tmpfs 7.0M 40.0k 7.0M 1% /tmp
/dev/mtdblock/4 1.7M 408.0k 1.3M 24% /jffs
mini_fo:/jffs 1.6M 1.6M 0 100% /
/dev/scsi/host0/bus0/target0/lun0/part2
1.8G 5.9M 1.7G 0% /mnt
I tak nie będę używać flasha w routerze 