i also had a problem that the apps wouldnt recognise my device as compatible when trying to install from online out of nowhere for some reason , then when updated it was fine.
brainapp doesnt auto download if i choose to installl from my laptop anymore only from the device does it work now, guess its the updates fixing and screwing up stuff.
svguy. brainapp is a market like andriod market look it up install their apk app and use that plus it records what you install incase of a factory reset is needed you have them stored online for you
plus dont forget the golden rule with this machine many apps fail to install if the sdcard is in the machine .