Upgrading your IOS image on the Integrated Service Router is a relatively straight forward procedure, but with several steps. After the desired IOS image has been downloaded, there are a few pre-upgrade steps that should be taken before upgrading the IOS image on the router. These steps along with the entire upgrade process have been provided below.

The official IOS upgrade documentation is also available here: Cisco IOS Upgrade Documentation


1. Set up a server on your workstation that supports one of these protocols (ftp, http, scp, tftp) and place the IOS image in the public directory.

2. Log into the router and make sure it can ping the workstation.
Command Example:
[linux-ws]$ telnet 192.168.1.60
Trying 192.168.1.60...
Connected to 192.168.1.60 (192.168.1.60).
Escape character is '^]'.
User Access Verification
Username: user
Password: <enter your password>
2951Router>ping 192.168.1.6
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.6, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5)
3. Get into privileged mode by typing 'enable' at the router prompt and entering a password if prompted. Notice that when you are in enable mode that the router prompt changes from '>' to '#'.
Command Example:
2951Router>enable
Password: <enter the enable password>
2951Router#
4. Check that there is enough space in the flash directory for the IOS image that you are about to copy. If there's not enough space you'll need to delete the old image via 'delete flash0:<filename>'.
Command Example:
2951Router#show flash0
-#- --length-- -----date/time------ path
9 60482156 Mar 16 2011 17:36:58 +00:00 c2951-universalk9-mz.SPA.151-3.T.bin
199827456 bytes available (60661760 bytes used)

5. On the router type 'copy <protocol> flash0:'. Enter data as requested by prompt. The router will load the IOS image.
Command Example:
2951Router#copy ftp flash0:
Address or name of remote host []? 192.168.1.6
Source filename []? pub/c2951-universalk9-mz.SPA.151-4.M.bin
Destination filename [c2951-universalk9-mz.SPA.151-4.M.bin]? <press the enter key>
Accessing ftp://192.168.1.6/pub/c2951-universalk9-mz.SPA.151-4.M.bin...
Loading pub/c2951-universalk9-mz.SPA.151-4.M.bin !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
[OK - 62590040/4096 bytes]

62590040 bytes copied in 54.948 secs (1139078 bytes/sec)
6. Check that the IOS image file is loaded by typing command 'show flash0'.
Command Example:
2951Router#show flash0
-#- --length-- -----date/time------ path
6 62590040 Apr 20 2011 00:13:08 +00:00 c2951-universalk9-mz.SPA.151-4.M.bin
9 60482156 Mar 16 2011 17:36:58 +00:00 c2951-universalk9-mz.SPA.151-3.T.bin

137236480 bytes available (123252736 bytes used)
7. Check the running configuration and see if the IOS command 'boot-system flash0:<IOS image>' is present. If it is present you'll need to get into configuration mode to remove this command and add a new one to boot up the new flash file. Save changes via 'copy run start'. Note that if there is only one IOS image in your flash0 directory or the image that you want to be loaded is on top of all of the other images that you do not need the 'boot system flash' command as the system will load that top image automatically.
Command Example:
2951Router#show run | sec boot
boot-start-marker
boot system flash0:c2951-universalk9-mz.SPA.151-3.T.bin
boot-end-marker
2951Router#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
2951Router(config)#no boot system flash0:c2951-universalk9-mz.SPA.151-3.T.bin
2951Router(config)#boot system flash0:c2951-universalk9-mz.SPA.151-4.M.bin
2951Router(config)#end
2951Router#copy run start
** Make absolutely certain that the IOS image file referenced by the 'boot system flash0:' command is spelled correctly.
8. Reload the router by typing 'reload' and press the 'enter' key when prompted.
Command Example:
2951Router#reload
Proceed with reload?
9. After the router has booted up, access it and check that the proper IOS image is loaded.
Command Example:
2951Router#show version | sec image
System image file is "flash0:c2951-universalk9-mz.SPA.151-4.M.bin"
10. The router IOS image has been upgraded.