Руководство По Установке для Cisco Cisco ASA 5585-X with No Payload Encryption

Downgrading to Version 8.1 or earlier—After you upgrade, if you activate additional feature 
licenses that were introduced before 8.2, then the activation key continues to be compatible with 
earlier versions if you downgrade. However if you activate feature licenses that were introduced in 
8.2 or later, then the activation key is not backwards compatible. If you have an incompatible license 
key, then see the following guidelines:

If you previously entered an activation key in an earlier version, then the ASA uses that key 
(without any of the new licenses you activated in Version 8.2 or later).

If you have a new system and do not have an earlier activation key, then you need to request a 
new activation key compatible with the earlier version.

Downgrading to Version 8.2 or earlier—Version 8.3 introduced more robust time-based key usage 
as well as failover license changes:

If you have more than one time-based activation key active, when you downgrade, only the most 
recently activated time-based key can be active. Any other keys are made inactive. If the last 
time-based license is for a feature introduced in 8.3, then that license still remains the active 
license even though it cannot be used in earlier versions. Reenter the permanent key or a valid 
time-based key.

If you have mismatched licenses on a failover pair, then downgrading will disable failover. Even 
if the keys are matching, the license used will no longer be a combined license.

If you have one time-based license installed, but it is for a feature introduced in 8.3, then after 
you downgrade, that time-based license remains active. You need to reenter the permanent key 
to disable the time-based license.

To downgrade from 8.3, perform the following steps.

For the CLI:

Enter the following command:

hostname(config)# downgrade [/noconfirm] old_image_url old_config_url [activation-key 

old_key] 

Where the /noconfirm option downgrades without prompting. The image_url is the path to the old image 
on disk0, disk1, tftp, ftp, or smb. The old_config_url is the path to the saved, pre-migration configuration 
(by default this was saved on disk0). If you need to revert to a pre-8.3 activation key, then you can enter 
the old activation key.

This command is a shortcut for completing the following functions:

Clearing the boot image configuration (clear configure boot).

Setting the boot image to be the old image (boot system).

(Optional) Entering a new activation key (activation-key).

Saving the running configuration to startup (write memory). This sets the BOOT environment 
variable to the old image, so when you reload, the old image is loaded.

Copying the old configuration to the startup configuration (copy old_config_url startup-config).

Reloading (reload).