I've seen several other sites doing trouble shooting on this issue - LG G3 keeps restarting unless charging, but I kept thinking "faulty battery" isn't really the cause as those sites have stated!
Why? Because my device won't restart even without charging in recovery or firmware download mode. I suspect it's something to do with the OS.
I don't know if it's coincidence or not, but my phone started doing so and getting worse only after I installed Root Booster, supposedly helping me boost my battery time and such.
Backstory:
It was fine at first, only restarting so often, but after I changed the mode in Root Booster and restarted, my phone entered battery saving mode (I saw in the lock screen, not charging, > 15% battery) and it restarted after only 0.5 a second after booting into the lock screen.
I then managed to unlocked the screen and changed the mode in Root Booster again. Then my phone began a restart loop again, but this time I can't see the lock screen.
Then when I came home and was charging my phone, it turned on OK and I thought changing the mode in Root Booster might get me better and I did so charging. And now not charging, my phone's restart loop can't even get past the LG logo to the "swoosh red face LG" animation.
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I then thought upgrading to Android 6 via KDZ upgrading might help me because I was still using 5.1, but no.
Please help! Is there anyway to deal with this without losing all my files?
Why? Because my device won't restart even without charging in recovery or firmware download mode. I suspect it's something to do with the OS.
I don't know if it's coincidence or not, but my phone started doing so and getting worse only after I installed Root Booster, supposedly helping me boost my battery time and such.
Backstory:
It was fine at first, only restarting so often, but after I changed the mode in Root Booster and restarted, my phone entered battery saving mode (I saw in the lock screen, not charging, > 15% battery) and it restarted after only 0.5 a second after booting into the lock screen.
I then managed to unlocked the screen and changed the mode in Root Booster again. Then my phone began a restart loop again, but this time I can't see the lock screen.
Then when I came home and was charging my phone, it turned on OK and I thought changing the mode in Root Booster might get me better and I did so charging. And now not charging, my phone's restart loop can't even get past the LG logo to the "swoosh red face LG" animation.
------------
I then thought upgrading to Android 6 via KDZ upgrading might help me because I was still using 5.1, but no.
Please help! Is there anyway to deal with this without losing all my files?
I asked to try out a new battery at the shops and it worked. Still hard to believe though. 
