I have just purchased the Samsung S24A350H that has Magic Tune but unfortunately(??) my graphics card is not supported so that I was unable to install it. I did see that there were problems caused by MagicTune on the forums, so I as not too bothered.However removing Magic Tune should not invalidate any warranty. It would not hurt to google MagicTune problems.
Amazon Fire HD 8 review: A brilliant combination of function and value – with one massive caveat