I am running a Firestick 4k with STB Emu version 1.1.9. Was having issues with it freezing and locking up, it would then boot me out. The fix I have found that works for me is to download VLC player and make it your default player, exit from the app, clear cache and restart.
Hopefully that will work for you, it has done for me unto now.
M
Hopefully that will work for you, it has done for me unto now.
M