3GX V3.1 update - now won't start

[malloryn]

I've just done an update to V3.1.
The update procedure seemed ok with "update complete message" with the 3GX software.

Now - when powering up I get just a red status light and 3-off-1 green lights (firmware version probably).
There's no servo movement, no getting into DIR mode and the unit will not respond to the USB interface.

Any ideas ?