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New Member

IOS upgrade problem

Hi , i whant to upgrade ios version .

I have new ios image on a tftp server , i know the upgrade procedures but there is a problem with my flash. Not enough space on it , also after trying to copy the new image from tftp server it is not asking me if i want to remove the old one. Some suggestions about solving this ? Also if i succeed i want a backup solution if the new flash doesn't boot properly. Thanks in advance.

Here the info needed :

Cisco router 1811

old IOS ver : Version 12.4(2)T1

new IOS ver : Version 12.4(9)T1

I'have an idea how i can backup the router if the new ios image doesn't boot properly. I will boot from tftp server new ios image , after i set this boot parameters the router will search new image file on the tftp server. So if the booting of new ios image fail i will just change the name of the file of old ios image on the tftp server with the name the router is searching so it can boot the old ios image , beacause we know it is ok.

Is this a good idea for backup ? :)

Thanks in advance


Re: IOS upgrade problem

It's OK to consider backup options. However, I would think there's a very good likelihood that upgrade would succeed if you are using the correct IOS for the platform.

You are probably aware of the fact the new IOS will kick in only after the reboot. You can reboot the router after making sure the image that you downloaded has a valid checksum, which the router would automatically display after it finished downloading the image. You can also verify this with the command 'verify flash' from the exec mode.

If there isn't enough space in the flash for the image though the router isn't prompting whether you want to delete the old image it would fail when it runs out of space during the download. Hence, you might want to delete/ the old IOS or format the flash before you download the new one.

As far as your backup options, you can download another image using xmodem or boot from the network.

Good Luck!!



New Member

Re: IOS upgrade problem


as i got your query i think just do 1 thing

first copy old IOS from flash to tftp ( You know the procedure).IF you don't then i'll give it to you

After copying the old image from flash to TFTP start loading new IOS from TFTP to Flash

IF your new ios fails your old IOS will with you and you can get it back

And 1 thing more if New IOS dosen't load well then your old IOS won't finish because TFTP just put New IOS In DRAM and reboot it and if IOS is fine then it will place automatically in Flash


New Member

Re: IOS upgrade problem

I have a similar situation where I'd like to boot a newer IOS image via tftp, and want to fall back to flash in the event of trouble. Problem is, I can't find any info that would tell me how to configure ROMMON to bring up an ethernet interface, and associate an IP address to it that I might contact the tftp server and get the IOS image. Does anyone have a link that could help? System is a 7603 with Sup2/MSFC2. Thanks,


Cisco Employee

Re: IOS upgrade problem


The ROMMON cannot bring up an ethernet interface and communicate with the tftp server. The only situation when I have seen this work is during tftpdnld procedure (used to copy the IOS to the flash in ROMMON mode) on certain routers. Else, whenever you want to boot the router/switch from an IOS on the tftp server, you would need atleast a minimum IOS (or bootimage) on the router which can bring the interface up and understand the boot statement which points to a specific file on a tftp server.

When the router would boot, the first file in the bootflash would be decompressed and used to bring the interface up and then the IOS on the tftp server (as pointed by the boot statement) would be decompressed and loaded in the DRAM.

As there are two files (the one in the bootflash and then the one on the tftp server) which are decompressed in the DRAM, we need to ensure that we have enough DRAM. You can try it with your existing file and see if it works. In case, it gives any error which indicates that you need additional DRAM, then install a minimum IOS version as the first file in the bootflash which would allow you to bring the ethernet interface up.

Important points:

1. The first file in the bootflash should be a valid IOS for the device.

2. The first boot statement should be pointing to the file on the tftp server. Its case sensitive.

Example: boot system tftp

3. The second boot statement should point to the IOS image that you would like to use as a backup. This image may be the same as the first file in the flash/bootflash or may be another file stored on a PCMCIA flash card/disk.

I hope this helps.


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