Question : Disaster Recovery on Cisco 837

Dear All,

I have a Cisco 837 ADSL router which has a corrupted IOS (boots only in rommon). I am following the procedures however I just keep getting the following error:

rommon 1 > ip_address=192.168.1.2
rommon 2 > ip_subnet_mask=255.255.255.0
rommon 3 > default_gateway=192.168.1.1
rommon 4 > tftp_server=192.168.1.1
rommon 5 > tftp_file=c837-k9o3sy6-mz.123-2.XE
rommon 6 > tftpdnld

Missing or illegal ip address for variable IP_ADDRESS                                                    
Illegal IP address.                  

usage: tftpdnld [-ur]
  Use this command for disaster recovery only to recover an image via TFTP.
  Monitor variables are used to set up parameters for the transfer.
  (Syntax: "VARIABLE_NAME=value" and use "set" to show current variables.)
  "ctrl-c" or "break" stops the transfer before flash erase begins.

  The following variables are REQUIRED to be set for tftpdnld:
            IP_ADDRESS: The IP address for this unit
        IP_SUBNET_MASK: The subnet mask for this unit
       DEFAULT_GATEWAY: The default gateway for this unit
           TFTP_SERVER: The IP address of the server to fetch from
             TFTP_FILE: The filename to fetch

  The following variables are OPTIONAL:
          TFTP_VERBOSE: Print setting. 0=quiet, 1=progress(default), 2=verbose
      TFTP_RETRY_COUNT: Retry count for ARP and TFTP (default=7)
          TFTP_TIMEOUT: Overall timeout of operation in seconds (default=7200)
         TFTP_CHECKSUM: Perform checksum test on image, 0=no, 1=yes (default=1)

  Command line options:
   -r: do not write flash, load to DRAM only and launch image
   -u: upgrade the rommon, system will reboot once upgrade is complete

Please advise.

Thank you,
REX

Answer : Disaster Recovery on Cisco 837

Set the ROM monitor variable TFTP_CHECKSUM to 0. This is done by defining the variable TFTP_CHECKSUM=0 from the ROM monitor set command, and then continue with the tftpdnld procedure.