Cisco ROMmon and IOS image Filed Under: Networks
Introduction
This tutorial is a continuation to a previous tutorial about recovery of IOS image using Xmodem connection. This tutorial will focus more on how to go to ROMmon and how to load a different image located in the switch from ROMmon if the one we have is not working.
Going into ROMmon
Routers
To go to ROMmon in a router you will need to restart the router and while the router is loading you need to press the key combination ctrl + break
.
Switches
To go to ROMmon in a switch you will need to restart the switch and while is loading you need to press the button on the front of the switch that is labeled “Mode”.
Initialization and loading an IOS image
Once you go to ROMmon the device will present you with a list of available commands:
flash_init
load_helper
boot
Once the ROMmon has loaded you’ll need to execute the command flash_init
so you can load the flash memory of the switch (we have the IOS images down there).
After that execute load_helper
.
Finally to load the IOS image you want into the switch you need to execute the command
boot <location of the IOS image>
boot flash:/c2950-i6q4l2-mz.121-22.EA2.bin
Changing IOS image
Just to let you know that the command boot from ROMmon will just load that IOS image at that moment if you reboot the switch the switch will start using the previous IOS image it had.
If you want to change the IOS image that the switch will use while loading you’ll need to execute the following command under global configuration mode.
boot system <location of the IOS image>
boot system flash:/c2950-i6q4l2-mz.121-22.EA2.bin
If you want to make sure that the location and the image the switch is going to load is ok you can check this by using the command show boot
.
How to know the content and path of a IOS in flash
To look at the content of the flash execute the command
show flash
The flash memory may contain the IOS images inside directories. To check the content of the directory first you need to execute the command cd flash:/<directory>
. This will change the present working directory to the directory you have specified so if you issue a show flash
the switch/router will show the content in flash of that directory.
If you want to go back to the root of the flash you’ll need to execute the command
cd flash:/
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- Alberto Diaz
- 22 Jan 2007 6:14 PM
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