[AC Question]

I have been using Oneplus one for like 1 year or so, and its a beast. OK without wasting time i have a problem:

1) it reboots continuously when at Boot animation, things i have already done>>

a)factory reset,
b)installed various other roms,
c)did unbrick technique,
d)flashed stock rom using ADB shell,
e)Erased and flashed persist.img,
F)contacted support team, they took a Remote session but all in vain

Phew!!! but no luck

NOTE:

it reboots only when i flash Android version 5.0 or higher.
On kitkat it works fine what could be the reason, This a'int a hardware problem i guess .

Bonus query :

When i got the oneplus after flashing many roms,
I noticed it shows only 1869 MB ram while its 3 GB (should be 2556 mb or so),

and 2.5/2,7 Gb in android version 5.0 or higher,

SO PLEASE ANDROID TECHS, HELP ME!!!!!!