Introduction
This document describes how to perform a software downgrade on a router that runs Cisco IOS® XE SD-WAN back to the original software.
Prerequisites
Requirements
There are no specific requirements for this document.
Components Used
This document is not restricted to specific software and hardware versions.
The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, ensure that you understand the potential impact of any command.
Note: This process for SD-WAN routers running releases prior to 17.2.x.
Problem
The user cannot configure boot system flash bootflash: image settings in order to boot the original Cisco IOS XE image:
router#config-transaction
admin connected from 127.0.0.1 using console on router
router(config)#boot ?
^
% Invalid input detected at '^' marker.
router(config)#boot system flash bootflash:c1100-universalk9_ias.16.06.05.SPA.bin
-------------------^
syntax error: unknown command
Solution
The procedure is similar to a software upgrade to Cisco IOS XE SD-WAN software.
- Copy the required software to the bootflash or upload to a USB flash drive.
- Ensure that the router is connected to a management console.
- If PnP is running, stop PnP in order to allow access to the CLI:
router#pnpa service discovery stop
- Change the config-register to 0x0:
router#config-transaction
router(config)#config-register 0x0
router(config)#commit
router(config)#end
- Verify that the config-register is set to 0x0 when the router reboots:
router#show bootvar
BOOT variable = bootflash:packages.conf,1;bootflash:prev_packages.conf,1;
CONFIG_FILE variable does not exist
BOOTLDR variable does not exist
Configuration register is 0x0
Standby not ready to show bootvar
- Reboot the router:
router#reload
Proceed with reload? [confirm] Yes
The router reboots and goes into ROMMON mode.
- Check the router bootflash in order to obtain the software image name to load:
rommon 1> dir bootflash
rommon 2> boot bootflash:c1100-universalk9_ias.16.06.05.SPA.bin
The router reboots with the previous software image.
- Set config-register to the original value (for example, 0x2102) after the reload and save it:
router#config terminal
router(config)#config-register 0x2102
router(config)#end
router#write
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