First, let me say, Remote Upgrades are Very Risky, I personally would recommend doing an onsite upgrade, just in case the upgrade goes south, otherwise, you could have a Router stuck in ROMMON, and some upset customers.
The method I use to upgrade Cisco Routers is:
Step 1. Download the IOS image from your Cisco CCO account under Support and Software Downloads
Step 2. Backup your Router Configurations, I normally do a show run and copy the configuration to a text file. You can also back them up many other ways, such as a tool like SolarWinds, TFTP, etc.
Step 3. Configure a TFTP Server on the same LAN network as the Router You want to upgrade. Point the source to a folder that contains the IOS Image, configure the TFTP to use the interface and IP that is on the same LAN network as the Router, and follow the directions of your sourced TFTP server, pretty simple. There are a couple of different TFTP Server Programs that I use on a Windows PC, one is SolarWinds has a TFTP Server Program, that is free, but you have to register with their website, and you will get emails from them, but not too many, The second one, has been around for a while, and was updated in the age of 64 bit operating systems. The second one was formerly known as TFTP32, but is now TFTP64. Both work good, and I have not tried any alternatives. Just search for TFTP server, and they should both be listed as results.
Step 4 Double Check the current version on the Router against what you want to upgrade to and Check the space available on the FLASH card and compare it with the size of the File that you have downloaded. If there is not enough room, then you will have to cautiously delete the Existing IOS Image on the Router, and then upload the new IOS Image. To both verify the current version and to check the space on the Flash issue the following command from Priviledge Exec Mode: enable
Router1# Show Version
What you are looking for in regards to current image is towards the beginning of the output:
System image file is "flash:c2900-universalk9-mz.SPA.154-3.M4.bin"
What you are looking for in space is about in the middle of the output:
Cisco CISCO2901/K9 (revision 1.0) with 2506752K/114688K bytes of memory.
Add the two numbers together to get the Size of the Flash.
Alternatively to verify the current version which you will need later, but this command does not give you the space on the Flash, issue the command:
Router1# dir
which will have an output similar to this:
c2900-universalk9-mz.SPA.152-4.M6.bin
Step 5 On your Router perform the following commands. Caution, do not reload the Router until you have verified the new IOS Image is loaded on the Router, and the Boot Option is set to use the new option, otherwise you will be stuck in ROMMON.
Step 5.a If you need to make space on your flash card enter the command:
Router1# delete /force /recursive flash:c3825-adventerprisek9-mz.151-4.M10.bin
where c3825-adventerprisek9-mz.151-4.M10.bin would be your existing IOS Image found in show version.
Step 5.b
enter these commands sequentially answering each prompt:
Router1# copy tftp: flash:
Address or name of remote host []? 10.0.0.2
Source filename []? c2800nm-advipservicesk9-mz.124-25g.bin
Then just wait and watch the "!!!!!!!!!!!!!!!!" go across the screen until the load is complete.
Step6. When load is complete Verify your load is on the flash by issuing the dir command again as shown above.
Step7.
Router1# configure terminal
Rt-2901-GW(config)# boot system flash:c3560-ipservicesk9-mz.150-2.SE8.bin ( which is your New IOS image file)
Step 8. Reload / Reboot your router with:
Router1# Reload
Step 9 watch your router and verify everything comes back online and is operational.
I hope that helps.
