If you have done the same mistake as I then downgrading must be done via special image supplied by Polycom. That's because the file system format has been changed.

Regards, __Yehavi:

2011/11/1 Yehavi Bourvine <yehavi.bourvine@gmail.com>

Hello,

I've upgraded our Polycom phones from firmware 3.3.2 to 4.0.0 and have the following oddities:

- On shared lines the call lists are "mixed":
   - No calls are in outgoing calls.
   - answered incoming and outgoing calls are placed in incoming calls.
   - unanswered incoming and outgoing calls are placed in the answered calls.
- When the destination is busy there is no busy sign on the screen - the call is disconnected immediately

and the phone returns to an idle state.

I've opened today a support call with Polycom, and will update when I get replies.

                        Regards, __Yehavi: