As I received one answer, I submit a summary of my test.
Following is my question :
> 
> I am trying to update the firmware on a AXPVME board from the version
> 3.8 CD-Rom. After the boot, I have a screen with information and I
> should enter a "Return" or "Control C". But at this time I can't enter
> anything and I need to reset the system. I try with the 3.7 CD-Rom and 
> I have the same symptom.
> Is there a specific way to update the firmware on a AXPVME board ?
> 
In fact I would install the new firmware before to install Digital UNIX
and I had no way to read the full release note for the AXPVme on the
CD-Rom. 
As I was not able to upgrade the firmware, I installed Digital UNIX on
my disk and I read the release note for the firmware on the CD-Rom.
When I do exactly what it is written in the Release Note, the firmware
update works correctly.
I have confirmed with backward tests where was the problem and I was
surprised to uncover that it was linked with the "mode" environment
variable.If at the console prompt I set the "mode" to "fastboot", I can
update the firmware. If the "mode" is set to "nofastboot", I have the
symptom which I described in my question. 
-- 
  Hubert Robitaille                    mailto:hrobitaille_at_encore.fr
  Responsable Support Logiciel
  Encore Computer S.A.                 http://www.encore.com
  B.P. 54     78185 St Quentin en Yvelines Cedex    France
  Tel.: +33/0 1 30 23 36 00             Fax : +33/0 1 34 60 43 95
Received on Mon Mar 24 1997 - 11:00:10 NZST