The routerboard was running ROS 2.9.50. I tried updating it to v3.30 via LAN cable but it failed and I've been unable to access it ever since.
I have followed the steps listed here, but every time I reboot the RB I see the following happening in the terminal viewer: The PC is able to connect via LAN cable to the RB and the two IP addresses used are in the same subnet. I've tried using straight and crossover ethernet cables but get the same result every time.

Am I doing something wrong?

Update the firmware via Bootloader and Serial Cable

http://routerboard.com/files/rb-2.18/adm5120-2.18.fwf
restart

update the ROS via the Bootloader

RGDS

thanks, but how do I do that?

It just hangs when it gets to this point... how do I send the data file across?

you have to start transfer from hyperterminal (send file)

Thanks for your help.

I've upgraded to v2.18, but it's still doing the same thing as it did in my first post. eg.

trying bootp protocol............................................................................. failed

What I notice is that there is no activity on the ethernet connection. A few packets are sent, but none are received.

I have checked the firewall, but it's not blocking Netinstall.

btw, one other factor that may be complicating things is that I'm unable to connect to the routerboard using its POE (ethernet 1) port as this was damaged by a power surge. Eth ports 2 + 3 work just fine though.

I just read in this thread that having a fried Eth 1 port will prevent Netinstall from working. One member suggested that he had overcome this limitation once before, but never followed his claim up with an explanation.

Ideas anyone?

I've figured out a workaround...

I connected my PC to the Eth 1 port (which is damaged) and changed the speed to 10Mbps / Full Duplex. I was then able to establish an ethernet connection and upgrade to RouterOS 3.30 as per the Netinstall wiki.

I had the same problem for quite a while; even though i had switched off my anti-virus. This was solved this by my checking to see if the windows firewall was active and then switching it off!