Linux's netconsole works much better when you can pass it the MAC address of the server. (otherwise it just uses broadcast, which everyone else on my network complains about :)
This sets the evn var "serveraddr" (to match ethaddr), so that you can pass it to linux with whatever bootargs you want to....
addnetconsole=set bootargs $(bootargs) netconsole=@$(ipaddr)/eth0,@$(serverip)/$(serveraddr)
I'm sure this is white space damaged - but you get the idea...
Index: net/net.c =================================================================== --- net/net.c (revision 1961) +++ net/net.c (working copy) @@ -1273,6 +1273,15 @@ /* are we waiting for a reply */ if (!NetArpWaitPacketIP || !NetArpWaitPacketMAC) break; + +#ifdef CONFIG_KEEP_SERVERADDR + if (NetServerIP == NetArpWaitPacketIP) { + char buf[20]; + sprintf(buf, "%pM", arp->ar_data); + setenv("serveraddr", buf); + } +#endif + #ifdef ET_DEBUG printf("Got ARP REPLY, set server/gtwy eth addr (%pM)\n", arp->ar_data)