I have used until now openatv-4.2-vuduo2-20150418 including all updates and installed openpli-4.0-beta-vuduo2-20150504_usb. The installations works, but after the 1st reboot I see the openATV bootscreen and then it hangs for more than 10 minutes with the openatv screen.
This is an info only, since I need a working box and I have to flash another image. It didn't help to use the power switch.