2017.07 U-Boot Kirkwood - NSA325 (no replies)

Hello yo the whole forum for my first post.

I'm waking my old NAS - Zixel and I have found all this nice job that I would like to apply.
I'm not very familiar with all this stuff and I do not have time to apply for the UART emergency serial interface (I have one it in any case if needed).
So I would like to do everything right at the first time.

I am startin with a stock uboot (at least this is my guess because I got this second hand)

1st Question: For this NSA325 I have to follow the The Marvell Dreamplug box installation procedure Right ?
At Step 1a the root password is my password.
At Step 1b I needed to change /dev/sdc1 with /dev/sdb1 (this is where my USB is mounted)
At Step 1c I'm stuck ... mount: according to mtab, /dev/sda1 is mounted on /zyxel/mnt/sysdisk
What shall I do ?

Thanks