The USB files for 2.6 are not being seen as a firmware upgrade on the 3.0 AV console. I'd like to downgrade to see if 2.6 is more fluid, but perhaps this console fits the description found in the release notes...
In the release notes it says, "Due to a hardware change, consoles that shipped with v1.1.2 installed are not able to be downgraded to prior versions. Attempts to do so will result in an error. This is expected behavior."