Downgrade Cisco ASR1001-X 17.x to 16.x

[johnlloyd_13]

hi,

i need to "downgrade" an ASR1001-x from 17.2.1 to 16.9.7.

do i just configure the boot system variable below?

no issue with ROMMON code as it's already up to date.

conf t

no boot system
boot system flash bootflash:asr1001x-universalk9.16.09.07.SPA.bin
boot system flash bootflash:asr1001x-universalk9.17.02.01r.SPA.bin

ASR1K#sh ver
Cisco IOS XE Software, Version 17.02.01r
Cisco IOS Software [Amsterdam], ASR1000 Software (X86_64_LINUX_IOSD-UNIVERSALK9-M), Version 17.2.1r, RELEASE SOFTWARE (fc2)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2020 by Cisco Systems, Inc.
Compiled Thu 09-Apr-20 23:25 by mcpre

[Leo Laohoo]

@johnlloyd_13, 

"Unpack" the IOS-XE file:  Cisco ISR & ASR 1k Routers: IOS-XE/Firmware Upgrade (Install Mode)

[johnlloyd_13]

hi leo,

your doc used an ASR1002 router. is the procedure the same for ASR1001-X?

your doc also didn't mention the source and target OS and don't have cisco references/links, so it's a bit hard to follow.

[Leo Laohoo]

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@johnlloyd_13 wrote:

your doc used an ASR1002 router. is the procedure the same for ASR1001-X?

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Yes, it is the same. 

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@johnlloyd_13 wrote:

your doc also didn't mention the source and target OS and don't have cisco references/links, so it's a bit hard to follow.

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The Release Notes will only provide instructions about how to unpack the firmware.  
The same Release Notes, however, will not provide instructions about how to upgrade the ROMMON and also not provide the GOTCHA section.