I'm on Android 7.1.1 build number a20 everytime I try to go back to a19 build it pauses and I've tried to do it over my computer as well. I've returned 2 axon 7's to Best buy now... First one speaker crackle and second one speaker crackle and apps crashing. Sometimes it will show an error message. For instance if I'm in Google play it will show an error message ask for my input. But if I'm in a 3rd party app or even say you tube or Facebook it will somewhat crash like if I almost hit the home button.. no error. This is irritating the heck out of me. I love this phone and I'm giving it one more shot with another one today. I'll let you know if it continues. Does anyone have this same issue or a way to resolve it. Seems to be a software issue.