enable the netinstall on all ports for devices having more than one ethernet port. In case only one port at once can be in netinstall mode, let it be the first port that reports link-up status just before the netinstall can begin (the first physically connected port).
Reason: Sometimes the port that is the only one usable port of the device to perform netinstall is broken so there is no other option how to make netinstall (mainly for devices without serial port).
I expect that it could be done by small routerboot modification. Hopefully.
You can install using a Serial cable. In RouterBOOT menu, go to Firmware Upgrade >> Serial (Xmodem), then, in telnet, select “Send File” >> Xmodem >> Point to the .npk location.
It might take about an hour, but works. Had do do that in a couple of rb1100ahx2 that wouldn`t netinstall. Worked perfectly.
Are you absolutely sure about this? I could swear that “Firmware Upgrade” over serial is for RouterBOOT upgrades (FWF file) only. I don’t think it can accept a system NPK to install to the NAND flash, but I confess I have never actually tried this. If it can, it is an undocumented feature (http://wiki.mikrotik.com/wiki/Manual:RouterBOOT), and I would honestly be shocked if this was possible.