How i root n910v 5.1.1

HOW I ROOT N910V
WITH ODIN
<OSM> Enter CS for MD5..
<OSM> Binary Check MD5.. Do not unplug the cable..
<OSM> Please wait..
<OSM> Checking MD5 finished Sucessfully..
<OSM> Leave CS..
<ID:0/015> Added!!
<ID:0/015> Odin engine v(ID:3.1100)..
<ID:0/015> File analysis..
<ID:0/015> SetupConnection..
<ID:0/015> Initialzation..
<ID:0/015> Get PIT for mapping..
<ID:0/015> Firmware update start..
<ID:0/015> SingleDownload.
<ID:0/015> recovery.img
<ID:0/015> NAND Write Start!!
<ID:0/015> cache.img.ext4
<ID:0/015> FAIL! (Auth)
<ID:0/015>
<ID:0/015> Complete(Write) operation failed.
<OSM> All threads completed. (succeed 0 / failed 1)

IN SCRENN PHONE
SECURE CHECK FAIL RECOVERY
ANY SOLUTION

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