Unity wont install on android device

Ok I had been working with unity for about 8 months now and I have installed succesfully many builds to my LG Optimus Black (I know a little old)

Right now I’m working with Unity 4, have installed some builds (even networking builds) on this device, last time I had the same problem “application not installed” translated the code from JS to C# and it ran without a problem.

Now I tried the same (its a basic WWW + Start server code) and I can install it in 3 other (friend) android devices but it wont install in mine.

Got Android 2.2.2 (if that matters)

I didn’t find a proper listing of supported Android platforms but this seems to indicate 2.2 is not supported. This page tells you to install at least Api level 9 which seems to mean Android 2.3: