I've just installed APM2 and all works correctly exception to one problem about startup.
When i connect it with USB all the leds flash right, i can to arm/disarm and so on, when i connect it with
lipo instead only the blu led work (of course the green and yellow tx/rx too) but the red led remains off, after i've done a reset all works fine.
So, every time i have to start to fly, first of all i have to reset the board after Lipo connection , is it normal?
Yes, that is common. We're looking into it, but in the meantime just reset. Probably a good idea anyway, given that the copter may not have been level when you put the battery in.