[OnePlus 7 Pro Guides, News, & Discussion] h8Aramex:
- In case some step fails, just make sure your bootloader is unlocked.

- I assume you have a working adb and fastboot. I used the official Google package: https://developer.android.com/studio/releases/platform-tools . It's possible you will still have an older version installed because some "pack" installed it and put it in your path. How to edit PATH? What is PATH?! https://www.howtogeek.com/118594/how-to-edit-your-system-path-for-easy-command-line-access/

- Advanced Reboot is an option so you can easily enter recovery/fastboot mode. Enable it in Developer Options. How to enable Developer Options? Tap Build Number several times.

I realize the guide is long but it's overly detailed. If you get stuck, have questions, just ask and I will also edit the OP to answer more questions / clarify on points I guess.

Let's go back to latest OOS9.

Make sure to back everything up. If you have Google One, you can do a backup there. If you have root, even better, you can do a full backup with TWRP. I would also copy every important files over to my PC as well - just in case.

Make sure you are unlocked. This can reset if you flashed a full system update or anything so just make sure. If not, unlock.

Grab the MSM toolkit - we will use this to flash back OOS9. See: https://xdaforums.com/oneplus-7-pro/how-to/msm-tool-guac-t3934691

In my case I didn't have to mess with drivers or anything, just had to run the tool as admin. However, do read the steps, follow them in case you run into any trouble. Also, I just plug in the phone from a power off state with VOL buttons held down, start it, and I can start the flash process.

At this point you are locked, but does not matter for now. Thing is, now you are on a bit borked image. The stock image has broken fastboot, and might be AA or BA. Point is, you have to flash the correct update at this point. Grab the correct 9.5.11 for your device (AA = global; BA = EU): https://xdaforums.com/oneplus-7-pro/how-to/oneplus-7-pro-global-repo-oxygen-os-t3930585

Just copy it up to your device and use System Update -> Local Update once again to flash it.

Now it's time to flash LineageOS 16.

Now it's time to bootloader unlock again. (Via Developer Options, enable oem unlock and advanced reboot, go into Bootloader, use fastboot oem unlock.)

Now download the latest LineageOS rom from the official site: https://download.lineageos.org/guacamole

Copy up the files to your phone. You can also use adb push at later step. I leave it to you. Copying up might be easier.

Use fastboot boot ...img to boot up the latest unofficial TWRP: https://xdaforums.com/oneplus-7-pro/development/recovery-unofficial-twrp-recovery-t3931322 . You need the .img, but also grab the installer. Make sure you grab the Pie version, LOS16 == Android 9 (Pie).

Once you are in TWRP, go Install, and pick the Lineage zip. Then make sure to do a Wipe from the TWRP menu.

Reboot, let phone boot LineageOS. Shut down once it's booted. No need to set anything.

Press VOL_DOWN + Power to go into Lineage Recovery. Press Sideload here.

You need to grab "Mindthegapps" package from here: http://downloads.codefi.re/jdcteam/javelinanddart/gapps and you need to use adb sideload ...zip to load it onto the phone. It will cry about the zip being unverified, just tap proceed.

Now, once it's installed, wipe again from LineageOS Recovery again. At this point, you can also sideload TWRP. You need to use the .zip, and again - make sure you have the Pie version.

Phew, we are almost there! Reboot, log in to Google, do whatever. Set up your device.

Now, finally, let's finish up with SafetyNet.

Once everything is done, install the Magisk Manager APK and grab the ZIP from here. Since you have TWRP, you can just grab the zip to the phone itself.: https://xdaforums.com/apps/magisk/official-magisk-v7-universal-systemless-t3473445

Enter TWRP by using Advanced Reboot, Install magisk ZIP.

Almost done!

Go into Magisk Manager, make sure all is green. Go into the left hamburger menu -> Downloads. Grab "MagiskHide Props Config", Install. Reboot.

Now you have to install "Busybox" from Play Store, and you need to install a Terminal Emulator from Play Store as well. Just grab any.

Go into BusyBox, grant root, Install.

Open Terminal, type "su", then type "props".

Just go through the menu system and pick your phone. Just type in a number, and enter. And so on. If you get stuck / afraid to do harm, just reboot the phone and install busybox again, open terminal again, try again. Or ask.

Upon rebooting as you go through the tool, SafetyNet should 100% pass upon reboot.