How to Reinstall Cisco IOS from Rommon mode.

You can reinstall any Cisco IOS from Rommon mode.  Here are the commands that I used to load a new image from my TFTP server located at address 192.168.1.24.

You will notice that during the configuration that I entered the ip address of 192.168.1.2 to the router that I intended to load the image onto.  Then I decided to give the router the ip address of  192.168.1.23.  No biggie, I just re-entered the IP_ADDRESS=192.168.1.23

See the screen shot below.

click to enlarge

Steps to installing Cisco IOS image in Rommon mode:

Power off/on router and immediately send the cntl+break command.

At the the rommon 1 >: IP_ADDRESS=192.168.1.23

At the the rommon 2 >: IP_SUBNET_MASK=255.255.255.0

At the the rommon 3 >: DEFAULT_GATEWAY=192.168.1.254

At the the rommon 4 >: TFTP_SERVER=192.168.1.24

At the the rommon 5 >: TFTP_FILE=c2600-adventerprisek9-mz.124-15.T9.bin

At the the rommon 6 >: tftpdnld

Answer yes to proceed.