Are you experiencing overheating issues with your S5? You may have noticed your Galaxy S5 battery heating up too.  This fix I am about to tell you can also be applied to other android phones like the LG G3, Sony Xperia Z2 or HTC phones. I noticed the message “Unable to increase the brightness further. The device is overheating” when my phone got hot for no apparent reason and with no CPU intensive app or game running.

To fix this issue:

Take off cover and battery and just put the backside of the phone in front of a fan or if you don’t have a fan nearby, just wave it in the air back and forth to get air in it. That helps it cool down. Next, put the battery back inside and then hold volume up, home and power buttons at the same time. You should get into recovery mode, while you are in recovery mode choose the option that says “Clear Cache”.  This will clear the catch.  Finally boot up your phone like normal and you should notice it is no longer overheating. When a phone is overheating, it drains battery fast so it is in your best interest to do something to fix the overheating problem. Some apps and games can also cause overheating.

S5 overheating fix