How to install Router image using TFTP server?

Today tip will help you to install the router IOS to a Cisco 2500/2600/2800/3800 series routers. First make sure, you have installed and configured any TFTP (Trivial File Transfer Protocol)server over the LAN port. If you are trying to boot up your router without an IOS, the nonworking router will boot up in ROMmom

mode and the router first prompt will look like this:

rommon>
 

First run the set command to verify the ROMmom default variables.

In this mode all commands are case sensitive.

rommon1>set
 
Now run the TFTP download command to start the restore image process then press the enter button. 

rommon 2> tftpdnld 
After running the tftpdnld command, the following information will appear as under:



Now type the following information, for example router ip address, mask and default gateway then tftp server address. 

rommon 3 > IP_ADDRESS=10.1.1.2                            (router ip address)

rommon 4 > IP_SUBNET_MASK=255.0.0.0                  (default subnet mask)

rommon 5 > DEFAULT_GATEWAY=10.1.1.2                (gateway address)

rommon 6 > TFTP_SERVER=10.1.1.1                          (tftp server address)

rommon 7 > TFTP_FILE=12.0(4)t                                  (IOS file name)                                                                                                                 

Now again run the tftpdnld command to start recovery process immediately. 

rommon 8 > tftpdnld 

IP_ADDRESS: 10.1.1.2

IP_SUBNET_MASK: 255.0.0.0

DEFAULT_GATEWAY: 10.1.1.2

TFTP_SERVER: 10.1.1.1

TFTP_FILE: 12.0(4)t 

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]:  Yes 

Receiving 12.0(4)t from 10.1.1.1 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

File reception completed.

Copying file 12.0(4)t to flash.

Erasing flash at 0x60100000 

Now run the reset command to restore router as factory default settings. 

rommon 16 > reset 

Now after some time, your router will boot up with factory default settings.