[U-Boot] netconsole in u-boot

[ong]

Dear support,

Am trying to configure out how to change my u-boot to be netconsole from serial console.

When i key in help in my u-boot start-up, i didnt seen any nc command.
U-Boot> help

May i know how to enable netconsole.
By adding following in u-boot/include/configs/at91sam9260ek.h
#define CONFIG_NETCONSOLE 1

and then with the following command, 
make distclean
make at91sam9263ek_config
make CROSS_COMPILE=arm-linux-
I get error a compile error
drivers/libdrivers.a(netconsole.o): In function `nc_tstc':/home/linux4sam/linux-2.6.24/u-boot-1.1.5/drivers/netconsole.c:233: undefined reference to `eth_get_dev'drivers/libdrivers.a(netconsole.o): In function `nc_send_packet':/home/linux4sam/linux-2.6.24/u-boot-1.1.5/drivers/netconsole.c:116: undefined reference to `eth_get_dev'make: *** [u-boot] Error 1/Ong