20241219 - New stuff

CRdroid

Now recommended is CRdroid. It's a fork of LineageOS and has a lot of extras.

Magisk Manager

Magisk manager provides root, which allows hiding of the unlocked bootloader so that Google Wallet will allow payment functions to work, and it allows modules to add functionality so the Play Store Integrity Fix will work.

Play Store Integrity Fix

This module allows magisk to fool the Play Store servers into thinking that CTS and Basic Attestation are good. This allows GOogle Wallet to work with NFC payments.

The process

The tools

You'll need to have an executable 'fastboot' and 'adb'
You'll want a CRdroid download ZIP
Get a Google apps distro like mindthegapps. Arm64 for the OnePlusOne 7Pro (Guacamole).
Add a magisk zip or apk (same file)
Add Play Store Integrity Fix

What to do

Get the phone into developer mode. Settings->System->About click 7 times and developer optios are enabled.
Allow bootloader unlock. Settings->system->Developer Options->Allow bootloader unlock

Boot the phone into fastboot. Usually volume up+down and power at the same time work.
Unlock the bootloader. Usually fastboot oem unlock. Yes, phone must be connected via USB.
Flash CRdroid. Depending on which recovery you have this is different. adb sideload will work. TWRP will work. LineageOS recovery will too.
Flash the Google apps
Flash the Magisk app
Copy the Play Store Integrity Fix to sdcard using adb push.
reboot

After reboot

You're now running CRdroid. It may take a while to boot (like 3-5 minutes).
Install Magisk Manager from the Play Store and make sure both Magisk Manager AND Magisk are updated and working.
In Magisk Manager enable zygote mode.
Banking apps/Google wallet: install magisk module Play Store Integrity Fix. Reboot.
Health apps (Libre3): install magisk module shamiko. Reboot.

You're now running CRdroid + Magisk + Play Store Integrity fix + Shamiko. Enjoy.

Additional notes

If Magisk didn't install properly, you'll need to take that CRdroid zip file, unpack it, put the unpacked boot.img on the sdcard, and have Magisk manager MANUALLY patch it (instead of "direct install".) Good news: you only need to do this once. Bad news: Yeah it's a 3 step process. Also for that reason I'm not facdef'ing a phone just to test out the granularity of these instructions.
If Magisk Manager shows Magisk installed and Magisk Manager installed you just need to go to Settings and enable Zygote, then (hide Magisk app and install Play Store Integrity module) in no particular order.

20230917 - THIS IS BEING EDITED as of 2115z (2115UTC) More info to follow.

Sometimes TWRP will fastboot boot and sometimes it just hangs forever and gets you back to fastbootd mode.
FemBoy (??) Recovery usually fastboot boots but then doesn't negotiate USB so no ADB no MTP so no joy.
Pitch Black (PBRP) Recovery can't be flashed but it can be sideloaded, and it can flash itself if booted.

STILL WORKING OUT A FOOLPROOF WAY TO GET THIS TO WORK without ending up in the fastbootd mode where you want to reboot to 'bootloader' (fastboot without the d) and can fastboot boot things or fastboot flash partitions.

Unlock OnePlusOne 7pro and install LineageOs, Magisk, etc. with Linux

The shortcut

Wipe everything
Install the older OnePlus 7Pro firmware.
fastboot boot twrp from any of the sources below although this one works
Reboot and now you have a fully functional (yet old OnePlus 7Pro

Restore ability to update system from local file

Settings -> System -> Update should have an option in the upper left that will allow updating from local sources. OnePlus disabled this as of Android 12 on the phone. Here's how we restore it:

Download and install 10_OPLocalUpdate_For_Android12.apk
Open the installed up (also available as an app in the app-drawer called System Update
Download and place on sdcard (adb push) 20_OnePlus7ProOxygen_21.P.41_OTA_0410_all_2112101753_downgrade_aedc7acc349149f9.zip
Select that downloaded file from system update local update and let it update
Reboot into fastboot and
```
fastboot flashall unlock
```

Install TWRP and LineageOS

Download 30_twrp-3.7.0_12-0-guacamole.img

fastboot boot twrp-3.7.0_12-0-guacamole.img

Download and TwRP install 40_lineage-20.0-20230827-nightly-guacamole-signed.zip
Download and TWRP install 40_Magisk-v26.2.zip
Download and TWRP install 40_NikGapps-fullnikgapps-arm64-13-20230902.zip
Download the following to /sdcard/Download/"
Download and place on sdcard twrp-installer-3.7.0_12-0-guacamole.zip

Magisk-v26.2.apk
Pixelify-v2.2.zip
safetynet-fix-v2.3.1-MOD_3.0.zip

Put it all together

Reboot
Run Magisk app and ensure it sees Magisk installed
add then install all three modules
Reboot

Personal notes;

1. install the apk
2. it creates a system update app that can do local install.  
3. copy the p.41...downgrade...zip to /sdcard
4. install it
- reboot into recovery then fastboot
# fastboot flashing unlock  [on screen press vol-down and power] and reboot
get into fastboot
fastboot boot twrp-version.img
advanced -> flash current twrp image
reboot recovery to ensure it works
mount disable/enable mtp to get adb devices to work
copy over lineagos
install it
same for magisk
set for twrp to flash after installing roms
get gapps, adb push to sdcard, reboot recovery

So in one fell swoop install Lineage, magisk, and gapps...
-- might not work, might have to do each on its own, let it initialize /data, and continue

Install safety net 2.3.1-MOD2 and not 2.4 to pass CTS profile match.