Downgrading Samsung Galaxy S4 from 4.3 to 4.2.2

[solisortum]

My Samsung Galaxy S4's battery used to last up to a day and a half before the software update back in November 2013. Now, it barely lasts 6 hours and I'm also having troubles charging it. I woke up with low battery. I put it on charge at around 8:30 A.M. and it's almost 2 P.M. but its still not completely charged. I have tried asking Samsung for help and they helped me do a wipe cache or something. Obviously, it hasn't done much. I really want to downgrade my phone to 4.2.2 but I don't want to root it because I don't want to loose the warranty. I was hoping that a factory reset would restore the device to the stock firmware but I'm not sure if it will.
Any help would be great. Thank you in advance!

 

[JamesBramble]

Have you thought your battery may be knackered.

Order a new one and give that a try...

Posted via my Samsung Galaxy S4

 

[solisortum]

I tried that too. The new battery dies at the same rate.

 

[LadyTravel]

I am having that same issue with the battery. Now, I'm also having issues with the volume. Strangely, I don't understand why updates cause so many problems. So how do I downgrade from 4.3 to 4.2