I deleted the root on my phone how do i get it back

Hey everyone
so i deleted the root on my m2 note
because i thought it will void my warranty
i deleted it by installing supersu and pressing delete root
Is there any way i can get the root back
i tried factory resting and i dont know how to reflash
i tried updating by downloading update.zip and pressing power + volume up
and pressed update didnt work
update and wipe data didnt work it says it got corrupted after checking firmware
can anyone help me?

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