Chosen Solution
I installed a new battery on my iPhone 6 and restored it via iTunes and now It randomly restarts after 30/40 seconds and it doesn’t load the battery health. Also when it turns back on it has 1% of charge then after 10 seconds or so it shows the correct percentage. Just before restarting it shows a black screen then after a moment it shows the apple logo and boots back up. It does not say anything about my battery.
ur battery may not be connected correctly or all the way some similar happened to me when i did not install a battery correctly or the battery connecter might be damnaged
