I was trying to get the menu key to work as app switcher (did it) and was trying to find out a way to have menu key long press act as menu. At some point the menu, back and power keys stopped working. I did have backup of the Generic.kl and I restored the original but the keys still aren't working (I've rebooted twice). Any ideas what to do other than reflash the phone and pop the knox?
EDIT: I copied the original build.prop and Generic.kl from backup and now the phone doesn't go past the first Galaxy S4 screen. It does boot to recovery when I remove sim-card but I'm not keen on losing my warranty yet so I think I have to take it to the shop :/