Need help and advise on SE P800

[cffoo]

I have one P800 but it is dead. Can't switch on but when i use ufs 3, it can detect that this p800.

Can someone help and explain to me

1. how to use ufs3 to upgrade its software?
2. please teach me to check the version of the phone and also teach me to select the relevant files to flash to the p800.

3. the charging light of the p800 is working but i can't switch it on.

please reply as i am a new user of ufs...

i am grateful for the help......