How to make and iphone 4s stop working?

Okay so I have a iphone 4s that is still under warranty and it keeps glitching or just dosnnt work properly and every week or so something happens this week the battery just got stuck at 1% and if I would restart it it wouldnt turn on till I charged it even if i charged it for a couple of hours i tried different chargers and no change
So i took it to the apple store and asked them if they would fix it and they just friken restored it and there like its fine

so just wonder if there's a way to destroy the firmware or the insides without opening or physically damaging it or doing anything that would void the warrenty.

No. The only possible way is to jailbreak and download junk from Cydia but they will find that out. Other then that the iPhone has pretty good security for that kind of stuff. Keep complaining to the apple store and they will do something of greater meaning the restoring.