Have you ever loaded a router with IOS that is too big for memory? If you have, then you have ended up in a problem and the router dumps you to ROM Monitor or ROMMON prompt.

In this How To we weill explain what to do.

There is a simple way to reload the router with the prior IOS from your FTP server and get the router back up quickly. From the ROMMON prompt, cut and paste the green commands below replacing the appropriate addresses and file names. The yellow highlighted items are output from the router (your output will differ slightly, ofcourse).

rommon 1 >set
PS1=rommon ! >
?=0
CRASHINFO=flash:crashinfo_19930306-103452
BSI=0
RET_2_RTS=
rommon 2 >IP_ADDRESS=172.16.10.102
rommon 3 >IP_SUBNET_MASK=255.255.0.0
rommon 4 >DEFAULT_GATEWAY=172.16.10.1
rommon 5 >TFTP_SERVER=172.16.10.11
rommon 6 >TFTP_FILE=c2600-telco-mz.122-8.T.bin
rommon 7 >TFTP_CHECKSUM=0
Rommon 8> set
PS1=rommon ! >
CRASHINFO=flash:crashinfo_19930306-103452
BSI=0
RET_2_RTS=
?=0
IP_ADDRESS=172.16.10.102
IP_SUBNET_MASK=255.255.0.0
DEFAULT_GATEWAY=172.16.10.1
TFTP_SERVER=172.16.10.11
TFTP_FILE=c2600-telco-mz.122-8.T.bin
rommon 9 >tftpdnld -r

The router should immediately start downloading the IOS image specified from the TFTP Server specified. Once the transfer is complete, the router should reload and come back to its normal operation.

We hope this helps!

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