I've hated the hardware keys on my Samsung tablet since I bought it. Even after a year, I have to be careful not to brush the keys with my palm or else I'm suddenly exiting the book I'm reading or web page I'm viewing.
I rooted the device to try and fix this, however the instructions I've found for enabling on-screen navigation (by editing build.props) either gave me a black bar with no navigation buttons or, on later Samsung updates, prevented my tablet from booting.
I finally got around to installing CyanogenMod 12.1 (cm_chagallwifi-userdebug 5.1.1 LMY49J 11fa7f9ea1), and I can enable on-screen navigation using the following command (taken from this question):
settings put secure dev_force_show_navbar 1
Now I need to disable the hardware buttons. Most instructions I've found indicate to edit /system/usr/keylayout/Geneic.kl and comment out the keys for HOME, BACK and MENU. I mounted /system as read-write and commented out keycodes 127 (Menu), 158 (back)and 172 (home). Yet after a reboot, my hardware keys are still enabled!
I also cannot disable the LEDs on the keys either. I found a script that attempt to do this sending a 0 to /sys/class/leds/button-backlight/brightness, which does not exist on my CM12.1 system. I can't find any other files under /sys/class/leds that seem to deal with the hardware button backlights either and there's nothing in the settings menu for them.
All I want is to be able to disable the hardware keys. Turning off the LEDs would be nice too.