This morning a friend and I went flying our I1's and flew 4 batteries each after new app upgrade. The lag on both I1's was terrible, both of us experienced app closing out in the middle of flights. He had 2 incidents of app closing during flight and I had 3 failure of app during mid flight, lag was terrible. (He is using a Tab 4 and I am using my Samsung Tab S 10.5) Been using these for quite sometime now, I have never had a app issue until now. So we went back to the house and decided to get 1 more flight to double check the app before reinstalling the old version. I check all sensor values before every flight and calibrate compass when we fly in different areas. Mind you, I have never had a issue with my I1 until now... (88 flights 481,994 ft. perfect) The reason why I'm posting this is because not only a flyaway occurred but something very different happened and it is cause for concern. GPS could have been the initial problem however atti mode was not functioning properly. Full battery, 17 satellites and Full Signal Prior to takeoff. IMU settings 1480, gps 1 ect... I had full radio and gps signal, battery 78%(at the time of incident) Timeline of events that occurred... :30 "Battery Signal Loss" came up for less then 2 seconds, went away. (TB48 7 charges total) 1:10 noticed "yaw" slowed as i was following his I1 then completely stopped 1:17 Flyaway occurred I1 turned and booted, I had no control 1:24 Emergency procedure, Switched to Atti to regain control, Atti stop the flyaway but still no yaw control, no forward flight, throttle ect. at all... Had full radio signal all radio functions all looked normal... 1:28 Hit GPS mode then tried RTH, It held position for then.. 1:32 Flyaway again different direction 1:35 Switched to Atti mode again, stopped flyaway but again no radio function at all, so you can see the wind drift... 1:59 Desperate to regain control, hit GPS then RTH again. It held position once again then 2:11 RTH seemed to be working 2:15 Started Flyaway again.... 2:18 Switched to ATTI again, finally radio regained control and brought it in... The reason for this post is, Even though Atti stopped flyaway, Control from radio was not responding even while in atti.