Firmware Downgrade 5.1 -> 4.1

[tfreitas]

I upgraded my firmware from P0M3-04-1-00 to the new P0M3-05-1-00. I would like to downgrade the firmware from version 5.1 back to 4.3. How can I accomplish this? When I try to downgrade the firmware I get an error message that says file P0M3-04-4-00.sbn cannot be found. I don't know how to resolve this issue. Any help would be appricated!

Thanks!

[aslam]

It says on the Cisco site that once you upgrade to 5.0, it is not possible to downgrade to an earlier version.

I think you may have to open a TAC Case. Check the following.

Release 5.0

Cisco has added image authentication to IP phone protocols, which means that tampering of the binary image is not allowed before the image is downloaded to the phone. Any tampering with the image will cause the phone to fail the authentication process and reject the image. Once you download the Release 5.0 image, you cannot downgrade to any earlier releases. See "Upgrading to Release 5.0 and Release 5.1" section.

Release 5.1

Release 5.1 is the second release of the signed Cisco IP phone image. Release 5.1 is compatible with Release 5.0 and later releases. Release 5.1 addresses user interface responsiveness and voice clipping issues. See "Upgrading to Release 5.0 and Release 5.1" section.

[tfreitas]

Well I figured it was something like that. Thanks for giving me the update. I knew someone would have the answer!

Thanks!