Routeboards can only netboot from network using ether1. This is limitation of board bios, not netinstall, but result is the same. You have to use ether1 and if it's defective, board is pretty much bricked.
On one very specific case I manged to get around this by loading netinstall from CF card (on RB600 that can boot from CF) and once netinstall loaded, it could communicate over ether2. But with most routerboards there is no CF slot and you can only boot from ether1 or flash, with no other option available.

Its a RB600A, to boot from a CF is only copy npk file into them ?

Its a RB600A, to boot from a CF is only copy npk file into them ?

Then you are really lucky. No, you can't just copy npk to card, you have to extract the netinstall kernel from netinstall.exe and directly write it to special partition on CF card.
Here I documented entire process: http://www.r00t.cz/Misc/MikrotikNetinstallFromCF
Just follow it step by step and you should get it to work. Once netinstall is running on RB, you can plug network cable to any LAN connector and it should appear available in netinstall.