[CISCO] 라우터 OS Downgrade (Cisco IOS-XE SD-WAN -> 클래식 Cisco IOS-XE 소프트웨어 )

Downgrade Software on Router That Runs Cisco IOS-XE SD-WAN to Classic Cisco IOS-XE Software

 

A. Introduction

This document describes how to perform a software downgrade on a router that runs Cisco IOS®-XE SD-WAN back to the original (ordinary/classic) Cisco IOS-XE software.

 

 

B. 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

 

C. Solution

The procedure is similar to a software upgrade to Cisco IOS-XE SD-WAN software.

1. Copy the required software to the bootflash or upload to a USB flash drive.
2. Ensure that the router is connected to a management console.
3. If PnP is running, stop PnP in order to allow access to the CLI:
   
   router# pnpa service discovery stop
4. Change the config-register to 0x0:
   
   router# config-transaction
   router(config)# config-register 0x0
   router(config)# commit
   router(config)# end
5. 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
6. Reboot the router:
   
   router# reload
   Proceed with reload? [confirm] Yes
   The router reboots and goes into ROMMON mode.
7. Check the router's 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.
8. 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# wr

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