Copy IOS image using FTP, not TFTP, on 2500 series

Unanswered Question
Aug 25th, 2009

Can it be done?

Trying to upgrade on my ol' 2501's to 12.3 turned into such a disaster; I had TFTP checksum errors ad nauseum, and many other probs.

A forum member told me the TFTP client in IOS (or bootstrap? it can't be in IOS if it's copying the images and erasing the Flash where the IOS actually resides, can it?) is actually rather weak; and that I should use FTP instead.

Well, I've got 3C Daemon FTP server installed on my laptop, but what I can't find is info on how you actually get the transfer going, using FTP.

I have this problem too.
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Joe Clarke Tue, 08/25/2009 - 12:14

The 2500s are run-from-flash devices. This means that the active image runs out of flash, and thus a 2500 cannot be typically upgraded while online. Instead, you reboot the device into boot helper mode (i.e. you run another, stripped down IOS image). The boot images do not support FTP transfers. Your only choices are TFTP or RCP (see ). TFTP should be fine provided you have a good network connection. The weakness in our TFTP client mainly stems from lack of large file support, but 2500 images should be under 32 MB, so this is not a problem.

CriscoSystems Wed, 08/26/2009 - 21:21


I did some experiments with that one router with the checksum errors, loading different images and replacing Flash SIMM's. The checksum errors were being caused by a faulty Flash SIMM.

I've copied IOS 12.3(24) into three other 2500 Series now via TFTP without difficulties.

(Of course, this means I now have to ACTUALLY study IPv6 for the more excuses!)

Thanks guys for your help on this.


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