Switch the box off, on the rear side.
choose in putty for serial connect, speed must be set to 115200 and choose you`re comport.
Put the box on, when you`re connection is oke, you wil see some text scrolling over the putty screen.
Now use the ctrl + c key to stop the booting.
copy the following line in the screen:
boot -z -elf flash0.kernel: 'rootfstype=jffs2 root=/dev/mtdblock0 rw mem=0x8000000 bcmrac=3`
The box now reboot from the flash, so watch you`re box.
Then open telnet with dcc and put in the following line.
flash_eraseall /dev/mtd5
and after that the following line
reboot -f
Then you`re box is running again.