C-20
Cisco 3900 Series, Cisco 2900 Series, and Cisco 1900 Series Integrated Services Routers Generation 2 Software Configuration Guide
Appendix C      Using ROM Monitor
  How to Use the ROM Monitor—Typical Tasks
Examples 
Sample Output for Recovering the System Image (tftpdnld)
rommon 16 > IP_ADDRESS=171.68.171.0 
rommon 17 > IP_SUBNET_MASK=255.255.254.0 
rommon 18 > DEFAULT_GATEWAY=171.68.170.3 
rommon 19 > TFTP_SERVER=171.69.1.129 
rommon 20 > TFTP_FILE=c2801-is-mz.113-2.0.3.Q 
rommon 21 > tftpdnld 
               IP_ADDRESS: 171.68.171.0
           IP_SUBNET_MASK: 255.255.254.0
          DEFAULT_GATEWAY: 171.68.170.3
              TFTP_SERVER: 171.69.1.129
                TFTP_FILE: c2801-is-mz.113-2.0.3.Q
     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 
     Receiving c2801-is-mz.113-2.0.3.Q from 171.69.1.129 !!!!!.!!!!!!!!!!!!!!!!!!!.!!
     File reception completed.
     Copying file c2801-is-mz.113-2.0.3.Q to flash.
     Erasing flash at 0x607c0000
     program flash location 0x60440000
     rommon 22 >
Sample Output for the set ROM Monitor Command
rommon 3 > set 
    PS1=rommon ! > 
    IP_ADDRESS=172.18.16.76 
    IP_SUBNET_MASK=255.255.255.192 
    DEFAULT_GATEWAY=172.18.16.65 
    TFTP_SERVER=172.18.16.2 
    TFTP_FILE=anyname/rel22_Jan_16/c2801-i-mz
What to Do Next
If you want to configure the router to load a specified image at the next system reload or power-cycle, 
see the “Loading and Managing System Images” section in Cisco IOS Configuration Fundamentals 
Command Reference.
Troubleshooting Crashes and Hangs (stack, context, frame, sysret, meminfo)
This section lists and describes some ROM monitor commands that can be used to troubleshoot router 
crashes and hangs. 
Most ROM monitor debug commands are functional only when the router crashes or hangs. If you enter 
a debug command when crash information is not available, the following error message appears:
"xxx: kernel context state is invalid, can not proceed."
The ROM monitor commands in this section are all optional and can be entered in any order.