I recently loaded an application onto my firestick that caused it to get stuck in restart loop mode. Pressing buttons on the remote to get it to reset itself did not work. The only way I could get it to reboot into safe mode was by attaching my PC keyboard into my OTG adapter and connecting it to the firestick. By pressing Ctrl, Alt, Menu, Printscreen and I simultaneously it will reboot into safe mode. You then can delete the conflicting app. I hope this will help someone who has a similar problem with their firestick