Kumar Raja

Device not authorized means . When you connect OTG to other mobile RSA Popup should display on other mobile . you need to accept it as yes . then only...

You can copy the adb binary file from Lollipop to your device then adb will work.

Download adb and fastboot from this site http://www.droidviews.com/use-your-android-device-as-pc-for-fastboot-and-adb/ And next if you have a root access you can copy those files to your /system/bin or i suggest you to install...

Please tell me if you have any oneplus whatsapp group or do you know anything about nethunter in oneplus 3