back and menu buttons not working.

hi sir

i am a phone software repair man. i have updated a galaxy s4 from 4.4.2 to 5.0.1. it is working but back and menu buttons not works.

after that, i installed android 5.1.1 custom roms, downgrading to original 4.4.2, doing all wipes using custom recoveries, but they didnt work.

please help me.

excuse me for poor english.

best regards