Upgrading IOS without network connectivity

[anup_bekal]

Hi

After upgrading one of our Cisco 2620 Router with a wrong version of IOS, the Router has lost all its interfaces. i.e. It does not show any interface at all in the show config.

What are the methods to retrieve the router back to its normal stage and upgrade with the correct IOS.

Thanks in advance for any suggestions.

Regards // Anoop

[ankurbhasin]

Hi Anup,

Not sure how come wrong IOS can delete the interfaces. Wrong IOS may delete the config but should not delete the interfaces.

Anyhow if it has really gone then you will not be able to do tftp at all and the best way will be to take it to rommon and do xmodem

Check this link will guide you how to xmodem for 2620 router

http://www.cisco.com/en/US/products/hw/routers/ps259/products_tech_note09186a008015bfac.shtml#download_2620

Once you are able to bring the router up with perfect code then you can reconfigure it or upload the backup config if you have one.

Best of Luck

Regards,

Ankur

[scottmac · Accepted solution]

If the network interfaces are down, your only other options would be:

- Re-load the proper IOS via the console port.

---The usual procedure is to crank up the baud to 15.4KBaud to reduce the load time. I've found that there's a time advantage to loading a minimum IOS (IP Only IOS), then once the interfaces are back up, load the larger version using TFTP (depends on what ultimate version you need to load).

You can configure the router in ROMMON to do a IOS system load via TFTP or to boot from a BOOTP/TFTP server.

Here's the link for a console port load:

http://www.cisco.com/en/US/products/hw/routers/ps259/products_tech_note09186a008015bfac.shtml

Here's the link for TFTP from ROMMON:

http://www.cisco.com/en/US/products/hw/routers/ps214/products_tech_note09186a0080110ed1.shtml

Good Luck

Scott

[Richard Burts]

The suggestions about loading the proper IOS by tftp from rommon or via console (xmodem) are good suggestions and you may need to do one of them. But one other possibility occurs to me. Depending on how much flash is available in the router and how the IOS update was done it may be possible that the old version of IOS is still in flash. If so adding an appropriate boot system command pointing at the old image would be the simple fix. The output of show flash from the router would show whether the recovery can be simple or wil be complex.

HTH

Rick

[anup_bekal]

Hi

Thanks for all. All the information were helpful, though Ankur & Scott provided me with the link to the same information.

Regards // Anoop

[paul.werner]

You may want to give Rick's post another look and some extra thought. That is one of the major advantages to having a bigger hard drive, er, flash, on that router. Specifically in a production network where test resources are not readily available, loading a newer (possibly less stable) version of the IOS onto the flash alongside the older stable version is an insurance policy you cannot pass up. If your flash is not large enough to hold two images at the same time, you may want to consider a flash upgrade as a good investment. Additionally, it is also another area where you can store not just your startup configs, but you can archive the older configs to see what changes you made to the startup config over time. You will likely need to partition the flash to store two images and there is adequate notes in the IOS documentation on how to do that. Good luck.

pw