Why can't my phone turn on?
My phone keeps rebooting on and off when I turn it on. How can I fix it?
The LG G4 was released in the US in early June 2015, as always focusing on high-end specifications and a refined fashion sense that makes it stand out in the premium smartphone market. Each version of the phone will have a different model number based on if it is sold by a carrier or unlocked (US or International). Some LG G4's are known to have bootloop problems.
In order to fix this issue you will need to hard reset your device.
(Make sure to back up all your files as they may be lost in this process)
1) Turn the power off.
2) Press and hold the Power key and Volume Down key on the back of the phone.
3) Release the Power key when the LG logo is displayed, then press and hold the Power key again.
4) Release all keys when the factory hard reset screen is displayed.
5) Press the Power key to continue or any of the Volume keys to cancel this process.
6) Press the Power key one more time to confirm the reset.
For other issues related to charging the LG G4, please refer to this Troubleshooting Guide: LG G4 Troubleshooting
I've just run into this issue. One potential cause is what LG admitted to earlier this year, which I was unaware of until this problem happened to me just now.
There's apparently a loose contact somewhere on one of the components (I can't imagine it would be anywhere else but the motherboard). LG will fix it if you are under warranty. I, on the other hand, bought mine off of eBay and am not under warranty. So... if anyone with experience knows where the loose contact is and somehow can create a guide for this, that would mean the world to suckers like me who are left clueless and optionless.