rommon>confreg 0x2142
rommon>i
router>en
router#copy start run
router#conf t
router(conf)#enable secret cisco
router(conf)#config-register 0x2102
router(conf)#int fa0/0
router(conf-if)#no shutdown
router(conf-if)#end
router#copy run start

(Взято с http://www.xgu.ru)