IOS image upgrade procedure

Technology: Setup
Area: Setup
Vendor: Cisco
Software: 12.X , 15.X, IP Base, IP Services, LAN Base, LAN Light
Platform: Catalyst 2960-X, Catalyst 3560

Before going into IOS image upgrade procedure, you have to check current device model, amount of flash memory, RAM memory available and bootvar configuration settings using show version command.

Router#show version
Cisco 2811 (revision 1.0) with 249856K/12288K bytes of memory.
Processor board ID FCZ131820UY
2 FastEthernet interfaces
1 Virtual Private Network (VPN) Module
DRAM configuration is 64 bits wide with parity enabled.
239K bytes of non-volatile configuration memory.
62720K bytes of ATA CompactFlash (Read/Write)

These check of parameters should be prerequisite to every IOS image upgrade. Choosing new IOS be careful with feature set and resources that are needed for new image. Current and future version image features are included in Cisco IOS software name (c2800nm-advsecurityk9-mz.151-4.M12a.bin). Before beginning of upgrade copy IOS image file from TFTP server (or wathever server you have and is supported by device) to router flash memory.

Router#copy tftp: flash:

It is strongly recommended to check the control sum of new copied image. Othervise you might experience issues during bootup or the router will not proceed with upgrade. You can perform this from IOS CLI:

Router#verify /md5 flash:/new_copied_image_name.bin

After the checksum is verified, change the bootvar to the new image to let the router know which image file to choose during bootup and reload the device.

Check current bootvar:

Router#sh run | i boot
boot-start-marker
boot system flash:/c2800nm-advsecurityk9-mz.151-4.M12a.bin

Set new bootvar:

boot system flash:/new_copied_image_name.bin

Reload the system:

Router#reload

After the system bootups check if the new image is in operation:

Router#show version

Cisco IOS Software, 2800 Software (C2800NM-ADVSECURITYK9-M), Version 15.1(4)M12a, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2016 by Cisco Systems, Inc.
Compiled Tue 04-Oct-16 03:37 by prod_rel_team