To load an IOS onto a router
using ROMmon mode via Ethernet cable:
- Start the TFTP server (make sure the file path is
correct and that you allow both transfer and receive)
- Connect to the router via Ethernet cable (an
Ethernet cable is preferred due to the large size of the file and the
maximum speed that data can travel over the console cable)
¨ Before the IOS is loaded it is important to make sure that your router
has enough memory to support the IOS. The router will allow an IOS to be
loaded even if there is not enough memory, in this case a smaller IOS will have
to be loaded.
- At the rommon prompt enter the following commands
(commands are case sensitive, and the use of the directional arrows and
tab auto complete function is not allowed):
address of the Ethernet port
mask of the Ethernet port
IP of the TFTP server (your local computer)
file name of the IOS file
- The router will then issue a warning message:
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
- Enter y, and the IOS will load
- Once loaded you must boot up the new IOS by
issuing the boot command
To load an IOS onto a router using ROMmon mode via the
Cisco console cable:
- Connect to the router using the light blue Cisco
console cable (make sure the RJ-45 connector is plugged into the console
port on the router) using the 9600-8-N-1 settings. The next two steps
(changing the console baud rate) are optional.
- In ROMmon mode, change the baud rate to 15200
using the confreg command.
the ROM monitor
¨ The router will guide you through changing the
registry. You want to press y to chang the configuration. The only other
change you need to make is the change to the console baud rate, set that to 7
you wish to change the configuration? y/n [n]: y
"diagnostic mode"? y/n [n]:
"use net in IP bcast address"? y/n [n]:
enable "load rom after netboot fails"? y/n [n]:
enable "use all zero broadcast"? y/n [n]:
disable "break/abort has effect"? y/n [n]:
"ignore system config info"? y/n [n]:
console baud rate? y/n [n]: y
rate: 0 = 9600, 1 = 4800, 2 = 1200, 3 = 2400
19200, 5 = 38400, 6 = 57600, 7 = 115200 : 7
the boot characteristics? y/n [n]:
the ROM Monitor
you wish to change the configuration? y/n [n]:
must reset or power cycle for new config to take effect.
- When you reset the router in your console window
you will see characters that you cannot read. You have to stop the
session and set your baud rate to 115200. This will let you
increase the speed that you use to transfer the file.
- At the rommon prompt enter xmodem -c
- When prompted, enter y to continue
- From your hyperterminal prompt, click on
transfter then send file
- Select the IOS image then change the protocol to
xmodem via the dropdown box then click send.
- After the IOS has been downloaded, change the
boot order by using the confreg 0x2102 command.