I have just completed building my new S900 with A2, H3-3D & iOSD Mk2 running spektrum sats & DX8 for radio link.  I have ensured that the firmware on all units is current having reinstalled the latest firmware just to be sure.  My problem is that my iOSD is only partially functional.  It displays sats, voltage, mode, height & the artificial horizon appears to work fine. However, the distance from home point & heading info do not work.  There is nothing displayed next to the D or Az symbols and the diamond at the top of the screen does not move during flight. My tests were conducted with >7 sats & waiting for green flashes prior to flight. Any help will be kindly appreciated. Thanks John

Ok, I resolved the problem though I don't quite know how!  I redid all the wiring from scratch and reinstalled all firmwares again... voila problem solved.  

Some times you have to go back to the basics.  Glad it is working for you.