sudden blackout with no reason.
can't power on !!
what should I do?
hold down both volume buttons + power button to boot again... hope it will works...
Try plug into the PC and see what happens. If it does show as diagnostics 900E then it's hard brick. If it's 9008 then it may be possible to revive.
A few people stuck on 900E mode and there is very little change to fix it sadly.