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How to downgrade IOS 15 to IOS 12.4

We have new cisco 881 ruther with

Cisco IOS Software, C880 Software (C880DATA-UNIVERSALK9-M), Version 15.0(1)M4, RELEASE SOFTWARE (fc1), in this software we have problem with integration with old routers which are on IOS 12.4.

So we are wondering is it posible to downgrade from IOS 15 to IOS 12.4?

apricioate any help

Leo Laohoo
VIP Community Legend

Yes you can.  I suggest you remove the config first before the downgrade.

I have tried that. But when we try to conect TFTP (which is on the same laptop that we use to comunicate with router) server to ours cisco 881 router we get error mesage.

Router# copy tftp flash (or when trying to back up "copy flash tftp")

(here we enter IP adres, file name)

and we get this error:

%Error opening tftp:// (Socket error)


We can ping the tftp server, the file is in the place. What is this socket error we do not know.

we would highly apricioate any help

Let me confirm few things here: ->Is that the IP you entered while doing copy tftp flash.

Do you have enough space in the flash to accomodate two IOS images?

Have you placed the IOS image 12.4 in the root of the TFTP server?

Which TFTP server are you using? Possible to use TFTP D32??


Amit is the IP we entered doing 'copy tftp flash'

There is enough space in the flash.

IOS image is in root of the TFTP server.

We are using TFTP D32 TFtp server, we tried others too.

tnx for asking



Can you ping the TFTP server from the router as well?

Do you have any firewall running on the server with the TFTP? If so, please try disabling it.

Could you try using FTP instead of TFTP?

Best regards,


Leo Laohoo
VIP Community Legend

Ok.  Does your router have a USB port?  If so, then format a USB stick to FAT16, copy the IOS into the USB stick and insert it into the router.  The command should be "copy usbflash0:IOS.bin flash:".

Hope that works.

This is a firewall issue you have to create a roll in firewall setting 

Scott Hodgdon
Cisco Employee


Before you make this move, you should be aware that IOS 12.4 has been End of Support since 2016:,Cisco%20IOS%20Software%20Releases%2012.4%20Mainline%20%2D%20Retirement%20Notification,and%20is%20no%20longer%20supported.

Scott Hodgdon

Senior Technical Marketing Engineer

Enterprise Networking and Cloud Group