I received my APM2 yesterday. After a USB cable problem that have been resolved I've got another problem today.

Yesterday I was able to upload firmware and view sensors in mission planner.

A few hours ago I managed to power the board using output 5v bus (jp1 on) everything seems to be ok.

But now I can't connect to the board.

In mission planner :

MAVLink readpacket read error: Le délai d'attente de l'opération a expiré.
Mavlink Bad Packet (crc fail) len 0 crc 65535 pkno 0

When trying terminal mode no response.I can see the RX diod blinking when I send commands but TX diod never blink.

When I try to upload a firmware mission planner says "no heartbeat" (see picture)

Power led (green) is on

3dFix led GPS (blue) Blink slowly (0.5Hz)

A led (Red) blinks  (1Hz)

B led is off

C led (blue) blink quicker than A (4hz)

I'm a little out of idea. What can I do ?

Thanks for your help !