my mom's F1 died. Totally cant turn on/charge. She was listening to spotify when it died. So shouldn't be the display issue.

Next would be either battery, charging port and finally motherboard.

So opened it and swapped battery/charging port with a spare F1 and phone still didnt come to life. So guess its motherboard KO dy..

Age was 4 years.
No games on it so the phone was not on heavy usage or abused, just regular netflix/youtube,facebook/online shopping and internet browsing.

Quite disappointing for it to suddenly die like that. Didnt show any symptoms as well. Was still snappy and lag-free up until the day it died out of the blue.

funnily the spare F1 died few months earlier than that, suspect corrupted memory hardware, either ram/rom. Because the phone will keep restarting into boot menu, and after wiping also doesnt fix it. but this phone was abused kaw2 by my brother, heavy gamer and phone dropped like nobody business so i cant say much as to its quality.

both F1 bought same time in December 2018, so should be same batch. Batch issue? 
Anyway, now planning to get F4 for her. Thoughts on this?