Bought from delhi saket oneplus store
Yes, Don't know how these guys getting the phone from Offline stores.
Now the official TWRP is available and you can use this guide to Root Oneplus 6 easily
Download OnePlus 5 OxygenOS 4.5.8
OxygenOS 4.5.8 OTA for OnePlus 5 – Coming Soon
OxygenOS 4.5.8 Full ROM for OnePlus 5 – Download Here
Guide for both the Rooted and Non-rooted Users to Flash this OxygenOS 4.5.7 on Oneplus 5.
Both Full ROM and OTA zip are available
Download OxygenOS 4.5.6 for Oneplus 5 - Direct Download Link of FULL ROM and OTA
Follow this guide, you can find the video there.
Root Oneplus 5 and Install TWRP
Follow this guide t o ROOT ONEPLUS 5
Download Oneplus 5 usb driver aka Download Oneplus 5 usb driver with full installation guide in this post. Oneplus 5 usb drive is very usefully...
From here you can download OTA and Full zip files and install the same on your phone...
Guide to install The ROM one oneplus 3