uno board not appearing on mac os x nor windows

Using Arduino IDE 1.x
1

Hi,

I have a new arduino UNO R2 board.
When plugged on mac os x, the green led lit and the orange one blinks (first I think to show the bootloader work and then regular pace like the blink sketch).
But it does not appear in serial port menu from arduino 1.0.1. It does not create a tty.* device in /dev/, it does not show in hardware -> USB list from System Information.app.
I then tried to flash the dfu as explained in this post :

Then I saw that the second wire is not necessary since in the R2 there is already a resistor.
I tried the dfu programmer but no device is found.
I tried to go through a hub (from my dell lcd) as explained here :
http://arduino.cc/forum/index.php/topic,88195.0.html
Nothing.
Then I tried to plug the board on windows XP on a thinkpad.
Nothing, no com port in System conf.

So it seems I have a new board with the mega8u2 not functioning.
What can I do ?
Is there a way to program the board through the ICSP ? How ?

Thanks for your help.

Sincerely,

2

I forgot some other tests I have done.
I tried the hack from here:
http://arduino.cc/forum/index.php/topic,108936.0.html.
No numbers are added to the /dev/tty.SerialPort created (modem type).
I tried the Loopback instructions from the first post of the forum.
Nothing.

3

Have you tried a different USB cable?

4

Yes !
That was one of the first thing I've done.

5

Do you have an in-circuit programmer (or another functioning Arduino to use as a ISP)? If so, you can program the 8u2 with the ICSP header next to the chip.

6

I have a teensy 2.0.
Is there a tutorial for this kind of arduino programming ? That is to use another programmer, plug it to the 8u2, and configure arduino to use that programmer...

Thanks.