Some customers complained that the NanoPi2 cannot boot Debian or Android normally or after an OS loads it will reboot quite often.
We got a fix for this issue. Please check this thread:

Sorry for causing these customers this trouble and we really thank all of you who have trusted us and have chosen our NanoPi 2. We cannot say the NanoPi2 is a perfect product but we will do our best to improve it and make it better.