Pixhawk Amber IO LED flashing

My first build, HEXA with Pixhawk v2. Using MissionPlanner v1.3.34 to load ArmCopter v3.3.2. Erasure & flashing works fine, but on completion I have FMU Amber (off) IO Blue (flashing) and IO Amber (flashing). note; amber flashes faster than blue, so not police lights. The main status LED double flashes yellow.

The Flight Data page of Mission Planner always flags RC Not Calibrated; even though I have run through all of the RC calibration routines.

In all of the Pixhawk vids I’ve seen the IO amber is extinguished post-firmware installation and the IO amber implies a fault.

I’ve re-flashed several times, with ArduCopter 3.2.1 and 3. to same effect. Strangellt though, the IO amber is extinguised when I flashed it with latest ArduPlane !/

I’d appreciate any guidance as to what can I look for to diagnose what’s wrong ?.

Forgot to mention, also tried flashing with QGroundControl v2.7.1. Erased fine, but programming failed about half way though saying;
Error flash failed.
Write failed.
OS error.
The I/O operation has been aborted because of either a thread exit or an application request at address 0x0005 b880.

Re-flashed with same response, then went back to MissionPlanner.

We can’t offer support for APM / MP since we know nothing about it, but for PX4 / QGC: Please download and use QGC 2.8, since 2.7 is pretty outdated.

Also make sure to not power your complete drone from USB and to use a decent quality USB cable and a port at the back of your machine, not a front panel.