出現這個問題一般是因爲IOS被刪了。
解決方法：
1、準備工具 -IOS文件 -TFTP軟件，下載地址：http://vdisk.weibo.com/s/DiFYT -網線 -電腦IP配爲跟路由器同一網段，本例中爲：1.1.1.2
2、操作步驟（rommon右邊的數字不用管）
rommon 19> IP_ADDRESS=1.1.1.1 //故障機的IP
rommon 20> IP_SUBNET_MASK=255.255.255.0 //掩碼
rommon 21> TFTP_SERVER=1.1.1.2 //TFTP服務器的IP，就是電腦的IP
rommon 22> TFTP_FILE=c3845-spservicesk9-mz.124-12c.bin //IOS的文件名
rommon 30> DEFAULT_GATEWAY=1.1.1.2 //這個不配好像會有點問題，建議配上。
rommon 34> set //查看配置
PS1=rommon !> CRASHINFO=flash:crashinfo_20080426-202103 BOOT= WARM_REBOOT= RET_2_RTS=19:27:14 UTC Sat Oct 6 2012 BSI=0 RET_2_RCALTS= RANDOM_NUM=1461179899 IP_ADDRESS=1.1.1.1
IP_SUBNET_MASK=255.255.255.0
TFTP_SERVER=1.1.1.2
TFTP_FILE=c3845-spservicesk9-mz.124-12c.bin
DEFAULT_GATEWAY=1.1.1.2 ?=0
rommon 35>
rommon 35> tftpdnld //把IOS上傳到故障機。
IP_ADDRESS: 1.1.1.1
IP_SUBNET_MASK: 255.255.255.0
DEFAULT_GATEWAY: 1.1.1.2
TFTP_SERVER: 1.1.1.2
TFTP_FILE: c3845-spservicesk9-mz.124-12c.bin **GE_PORT: Ge0/0 //默認是使用G0/0**。
TFTP_MEDIA_TYPE: Copper GE_SPEED_MODE: Auto Invoke this command for disaster recovery only. WARNING: all existing data in all partitions on flash will be lost! **Do you wish to continue? y/n: [n]: y //輸入Y** Mac Address: 0015.c666.bc70 Receiving c3845-spservicesk9-mz.124-12c.bin from 1.1.1.2 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! File reception completed. Copying file c3845-spservicesk9-mz.124-12c.bin to flash. program load complete, entry point: 0x8000f000, size: 0xc0c0 Initializing ATA monitor library....... Format: All system sectors written. OK... Format: Operation completed successfully. Format of flash: complete program load complete, entry point: 0x8000f000, size: 0xc0c0 Initializing ATA monitor library.......
rommon 36>
rommon 37> reset //重啓機器就OK了。