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

  1. Wipe everything
  2. If you use fastboot flashall -w o adb wipe, just get rid of everything.
  3. Install the older OnePlus 7Pro firmware.
  4. fastboot boot twrp from any of the sources below although this one works
  5. Reboot and now you have a fully functional (yet old OnePlus 7Pro
  6. Here's where you can install TWRP, MAGISK, safetynet, etc.

    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:

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

    Install TWRP and LineageOS

    1. Download 30_twrp-3.7.0_12-0-guacamole.img
    2. fastboot boot twrp-3.7.0_12-0-guacamole.img
    3. Download and TwRP install 40_lineage-20.0-20230827-nightly-guacamole-signed.zip
    4. Download and TWRP install 40_Magisk-v26.2.zip
    5. Download and TWRP install 40_NikGapps-fullnikgapps-arm64-13-20230902.zip
    6. Download the following to /sdcard/Download/"
    7. Download and place on sdcard twrp-installer-3.7.0_12-0-guacamole.zip
    8. Magisk-v26.2.apk

      Put it all together

    1. Reboot
    2. Run Magisk app and ensure it sees Magisk installed
    3. add then install all three modules
    4. 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.