Hello @Alundra, we are sorry for the inconvenience and the trouble. We suggest when you updating Fota, you need to ensure your phone is connected with a stable network and has at least 30% battery power left to ensure you can update safely.
For now, we highly advise you to do a factory reset and after that, you tried to do the FOTA update again. This is the steps on how to do a factory reset.
Please kindly backup all your data first before doing The Factory Reset.
Warning: this action will erase all your personal information, files and downloaded apps.
In power on state:
Click " Settings" -> " Backup & reset" -> " Factory data reset" -> " reset phone"
In Power off state:
1) Long press Power Key and Volume Up Key
2) Use volume up key to select "Recovery Mode" and use volume down key to confirm.
3) Press Power Key and Volume Up Key together twice to enter recovery mode.
4) Press volume down key to select Wipe data/ factory reset
5) Press volume down key to select " Yes---delete all user data".
If the problem still existed, please contact our service center.