Nishant_Surte , via OnePlus 6 , Jun 26, 2020 : *LAST EDIT - 21st May, 2021 - Updated links to TWRP, added steps to flash custom rom as well* Requirements - 1. Oneplus 6 running on OxygenOS 10.3.x based on Android 10. 2. Windows PC 3. Files : Magisk - https://github.com/topjohnwu/Magisk/releases TWRP IMAGE file - Download twrp-3.5.2_9-0-enchilada.img TWRP ZIP file - Download twrp-installer-3.5.2_9-0-enchilada.zip 15 Seconds ADB installer - https://forum.xda-developers.com/showpost.php?p=82441649&postcount=1682 *also, I will update links if there are any updates in the given files* *also remember to take a backup of your entire data as this process involves formatting entire data* Steps Involved - 1. Unlocking Bootloader 2. Replacing stock recovery using TWRP recovery 3. Flashing Magisk for root access Firstly, install 15 seconds ADB installer on your PC. Then, copy all the other four files in adb folder (wherever you have installed 15 seconds adb setup). Then go to your phone and click on 'build number' several times until you see 'you are now a developer'. Then go to developer options and turn on OEM unlocking, USB debugging, and Advanced Reboot. Press and hold power button (you will see the option of BOOTLOADER) and boot your device into 'bootloader'. UNLOCKING BOOTLOADER (this will erase all your data) : Now on PC open command prompt in adb folder by typing cmd in the address bar (where you have placed all the rooting files), and hit enter. Give command 'fastboot devices'. There, if you see a serial number then your device is properly connected in fastboot mode. Now enter the command 'fastboot oem unlock' and hit enter. On mobile you will see a screen where it will give you two options - select Unlock the bootloader using volume key and press power key to unlock the bootloader. Once the device boots up complete the initial setup (No need to fill your email etc. for now, skip all that) and go to settings, about phone and tap on build number 7 times. Then go to developer options and there you will see that the oem unlocking option turned on because the bootloader is now unlocked. Now Turn on advanced reboot and USB debugging. Now boot your device into bootloader. Now on PC, check again if your device is properly connected in fastboot mode or not by giving the command 'fastboot devices' using command prompt. If your device is properly connected then the serial number will show up on your pc screen. Now on your pc, go to the adb folder and copy the name of the image file. Go to command promt and give the command 'fastboot boot (image file name).img [add dot img at the end of the file name as it is an img file] And hit enter. Now your device will temporarily boot into TWRP recovery. In TWRP, go to Wipe>Format data>type 'yes' and click on the tick mark on your mobile keyboard. Then go the home page of TWRP > reboot > bootloader. Again on your pc, give the command fast boot boot (image file name).img and boot back to TWRP Recovery. Once you're back to recovery, copy the magisk & TWRP zip files to your mobile from your pc. Go ahead and click install TWRP zip and flash it, followed by flashing magisk zip file. You can also flash custom ROMs in the same way, the steps are same, you just have to copy the ROM, twrp zip and magisk zip in the internal storage. The order of flashing a custom ROM is 1. ROM.zip, 2. TWRP.zip (reboot to recovery for slot change) 3. GApps (if not included in ROM) 4. Magisk.zip 5. Wipe>Format data (necessary after installing custom rom, not necessary if you are just rooting device) 6. Reboot system Press home button to come back to the main screen and click Reboot. Click on system. Your device will boot up. You have now successfully replaced official recovery by TWRP recovery and have properly installed root access on your device. This method is tested. However, I'm not responsible for any damages caused to you by you. If you have any questions or corrections feel free to comment on this thread.