MikroTik

Hi, I have bought a RB411, it works good.
I have bought a RB433AH in a second time from a supplier.
RB411 is more fasther than RB433.

On RB433 I've seen there are some differencies: if I type the IP address on browser I see an advertising web page from vendor, so I think there could be something changed from original configuration.

I alse find several times the log error message (rebooted because kernel failure) I haven't on RB411.

Now if I'm right, I think I could solve problems formatting nand (right?)

My questions are these:
1) how can I format nand? (I suppose I can find instructions on forum)
2) how can I keep license?

Thanks.

1) http://wiki.mikrotik.com/wiki/Manual:Netinstall
2) /system license output, that creates a XXXX-XXXX.key file in the root file system, you can copy it off via FTP or SFTP.

Well, I install netinstall; my pc has ip 192.168.83.56, I set in net booting ip 192.168.83.22.
I set routerboard to boot from ethernet:

trying bootp protocol... OK
Got IP address: 192.168.83.22
resolved mac address 00:xx:yy.....
transfert started .... transfert ok, time=2,24s
setting up elf image... OK
jumping to kernel code
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)

What's wrong?
There could be a third parties firmware not so good?